How to automate invoice chasing in field service

Automating invoice chasing doesn't have to mean losing control of your accounts receivable process. By setting clear rules around which invoices need chasing, when reminders should be sent and which accounts need a more personal approach, you can build a consistent routine that saves time without losing the human touch. For example, automations can handle overdue invoice lists and routine payment reminders, while disputes, payment plans and accounts on stop remain firmly in your team's hands. Your job management system remains the central record.

While writing an invoice chaser email only takes minutes, finding who needs chasing, checking previous replies and collating the information clients request can take considerably longer. For field service businesses, these small administrative tasks quickly add up.

In this article, find out why field service invoices become overdue, how to create an effective invoice chasing process, get examples of payment reminder emails and see the different options available for automating invoice chasing.

Why do field service invoices go overdue?

In field service, an overdue invoice often has a reason behind it that a reminder will not fix:

No purchase order number: Many facilities and housing clients will not pay an invoice without their PO on it.

A query about the visit: If the client wants to see the worksheet, the time on site or the parts before they approve the invoice.

Missing evidence: If the certificate, the photos or the signed worksheet is not on the job, the client's accounts team or portal may send the invoice back.

Never raised: If the job was completed but the invoice is still waiting, there won't be anything to chase.

The law sets the default for when an invoice is late. If no payment date is agreed, a payment between businesses is late 30 days after the customer receives the invoice or the work is done, whichever is later, and an agreed date should usually be within 60 days, according to gov.uk's guidance on late commercial payments (opens in a new tab), (on 30/10/2026).

As an example, if 40 invoices past their terms on the same day, and it took 3 minutes to find each invoice, check the inbox and write the chaser email, that would result in 2 hours of administration before difficult conversations begin.

How to set up a chasing routine that runs itself

Most of the work in invoice chasing follows a rule, and anything that follows a rule can be automated. Whatever software you use to run your automations, settle these five things first:

1. Fix the paperwork before the invoice. Check every completed job for the client's PO number, the signed worksheet and the photos before it is invoiced. An invoice that goes out complete is one you rarely have to chase.
2. Raise what was missed. On the 1st of each month, list last month's completed jobs that still have no invoice, by customer and value. Unbilled work is money you cannot chase yet.
3. Chase in stages. A polite reminder at 14 days overdue, a firmer chase at 30 and a statement at 60 is a common pattern. Write the wording for each stage once, in your own tone, and reuse it.
4. Build one list, at the same time each week. Monday at 09:00, the invoices between 30 and 60 days overdue, read from wherever payments are recorded. Reconcile the bank first, or a client who paid on Friday gets chased on Monday.
5. Leave the right people alone. Skip anyone who has paid, anyone already in an email thread with accounts, and anyone with an open query.

What should an invoice chasing email say?

A polite chase is short and specific: the invoice number, the amount, the site, the date of the work and how to pay. Name the job, because the person paying was rarely on site, and send it from a named person in accounts, not a no-reply address. Three examples to put in your own words:

14 days overdue. Hi [name], a reminder that invoice [number] for £[amount], for the work at [site], was due on [date]. It is attached again with the signed worksheet. If anything is holding it up, such as a missing PO number, reply here and I will sort it today.

30 days overdue. Hi [name], invoice [number] for £[amount] is now 30 days overdue. Could you let me know when it will be paid? If there is a query about the visit, reply here and I will send the worksheet, times on site and photos.

60 days overdue. Hi [name], attached is a statement showing £[amount] overdue across [count] invoices, the oldest from [date]. Please arrange payment within 7 days, or call me on [phone number] to agree a plan.

What should stay with a person?

Anything that needs a judgement about the client relationship stays with a person: a disputed invoice, a payment plan, putting an account on stop and any legal step. Software can gather the evidence and draft the reply, but someone who knows the client decides what to send.

Should you charge statutory interest?

You can, and it is a decision for a person. A business can charge statutory interest at 8% plus the Bank of England base rate, unless the contract sets a different rate, according to gov.uk on interest on late payments (opens in a new tab), (on 30/10/2026). It can also claim a fixed sum for the cost of recovery, once per invoice: £40 on a debt up to £999.99, £70 from £1,000 to £9,999.99 and £100 on £10,000 or more (gov.uk on recovery costs (opens in a new tab)). Interest is claimed on a new invoice.

What about BigChange, Joblogic and Simpro?

In all three, the invoice is raised in the job system and passed to the accounts package. So a good chase needs both: what is unpaid, from the accounts, and the job behind it, from the job system. Each vendor's guide below was read on 28/10/2026.

BigChange

BigChange pushes invoices, credit notes and purchase orders to Xero, and you choose whether payments are recorded in BigChange or in Xero, according to BigChange's Xero guide (opens in a new tab). The chasing itself still happens in someone's inbox. See BigChange and Xero.

Joblogic

Joblogic sends approved sales invoices, credit notes and payments to Xero, on a sync you run as often as you choose, according to Joblogic's Xero integration guide (opens in a new tab). When a client asks for evidence, someone still opens the visit and its jobsheet by hand. See Joblogic and Xero.

Simpro

Simpro's accounting link sends customer invoices and credits to Xero with the job number as the reference, according to Simpro's guide to the data exported to Xero (opens in a new tab). That job number is what lets a chase name the site and the work. See Simpro and Xero.

Which is the best way to chase: by hand, Xero reminders or an AI agent?

Each has a place, and many finance teams use more than one.

By hand, from a spreadsheet. Nothing to set up, and every email gets a person's judgement. It is also the first job to slip in a busy week.

Xero's own reminders. A sensible first step: Xero can send up to five automatic reminders before or after the due date, for invoices marked as sent, from templates you edit, and can skip balances under an amount you set, according to Xero's guide to invoice reminders (opens in a new tab), (on 04/11/2026). They work from the invoice alone, so a client in the middle of a query receives the same reminder as one who has gone quiet, and replies go to the one address set in Xero.

A general automation tool. It can send an email when an invoice passes a date. Reading the inbox, the job and the tone of the last reply takes a lot more building, and someone has to keep it running.

An AI agent. It reads the accounts, the inbox and the job before it writes, so it can skip the client with a query and name the site in the chase. It still needs your rules and wording, and a few weeks of checking before you trust it on larger amounts.

Whichever you use, decide which one handles each stage, so nobody is chased twice in a week.

How does Centrus help?

The Monday chase. An agent in Agent Builder loads invoices 30 to 60 days overdue from BigChange, Joblogic, Simpro, your spreadsheet or Xero, skips anyone already in a thread with accounts, and sends the chase in your tone from Gmail or Outlook.

The PO before the invoice. When a job is completed without a client PO, an agent emails the site contact and writes the reply onto the job (client PO check).

The query. Chat pulls the worksheet, times, parts and photos behind an invoice and drafts the reply for finance to check (invoice query evidence).

See the chase overdue invoices agent, and the rest of the finance work on finance and cash flow. To see the Monday chase on invoices like yours, book a demo with us.

Frequently asked questions

When is an invoice legally overdue in the UK?

If you have not agreed a payment date, a business payment is late 30 days after the customer receives the invoice or the work is done, whichever is later. An agreed payment date should usually be within 60 days. Your contract terms come first, so put the date on every invoice and chase from that.

How often should you chase an overdue invoice?

A common routine is a polite reminder at 14 days overdue, a firmer chase at 30 and a statement at 60, then a phone call. Chase on the same day each week, and stop as soon as someone replies with a query, so the next step is a conversation.

How long can you chase an unpaid invoice?

In England and Wales, you can usually bring a claim for an unpaid business invoice for six years from the date it fell due, under section 5 of the Limitation Act 1980 (opens in a new tab), (on 04/11/2026). In Scotland it is usually five years (opens in a new tab). Chase long before either: the older the invoice, the harder the evidence is to find.

Can AI chase invoices for me?

Yes, for the routine chases. An AI agent can read which invoices are overdue, check the inbox for a reply or an open query, and send the chase in your wording from your own mailbox. Disputes, payment plans and accounts on stop stay with a person, and it is worth checking its chases before trusting it on larger amounts.

Will an automated chase annoy clients who have already paid?

It should not, if it checks two things before it sends: the paid status after the bank is reconciled, and the accounts inbox for a reply or an open query. A chase that only reads the due date will reach clients who paid yesterday or are waiting for your answer, which is where most complaints come from.

Does Centrus chase from my own email address?

Yes. The chase goes from your accounts mailbox in Outlook or Gmail, signed by the person you choose, so replies come back to the inbox your team already works from. Every chase sits in Sent Items as normal, and the job system and Xero stay the record of what is owed.