How to get customers to pay overdue invoices by SMS

Most small businesses in Australia are not slow at the work. They are slow at getting paid for it. An invoice goes out, the due date passes, and the follow up sits on a mental list that never quite reaches the top. A month later you are effectively lending money to a customer at zero interest, and you did not agree to that.

Email is where invoice reminders go to be ignored. A text message is opened, usually within minutes. That difference in attention is the whole reason SMS works for getting paid. Below is how to do it properly, including the actual words to send.

Why a text gets a response when an email does not

An overdue invoice email lands in an inbox next to forty other emails, half of them marketing. It is easy to leave for later, and later never comes. A text sits on the lock screen. Your customer reads it whether they meant to or not.

There is a second reason, and it matters more. A reminder that includes the actual amount and a working pay link removes the excuse. Nobody has to log in to find the invoice, dig up a reference number, or reply asking you to resend it. They tap the link and pay. Friction is what kills payment, and a good reminder removes friction rather than adding a demand.

Hi Sarah, invoice #1042 for $680 from Coastline Plumbing was due on 6 September. You can pay it here: pay.sms365.com.au/x7Qk . Thanks, Dan.

That is polite, specific, and it can be paid in the time it takes to read it. No PDF to open, no login.

Get the timing right

The single biggest improvement you can make is sending on a schedule instead of when you happen to remember. A reminder that arrives the moment a customer feels overdue is easy to ignore because it feels automated and slightly rude. A reminder that arrives at sensible intervals reads as a business that keeps good records.

A schedule that works for most trades and services:

• Three days before due: a friendly heads up. This alone lifts on-time payment noticeably.
• On the due date: a short "due today" note with the pay link.
• Three days overdue: a firmer reminder that the invoice is now past due.
• Seven to fourteen days overdue: a direct message that references your terms.

The point is that the customer hears from you before it is a problem, so the overdue message is never the first contact. If you want the mechanics of automating this from your accounting system, see how to set up automatic overdue invoice reminders from Xero.

Keep the tone on your side

The instinct when someone is late is to get sharp. Resist it for as long as the relationship is worth keeping. A blunt demand at day three can cost you a repeat customer to save yourself four days of waiting. Stay warm and factual, and let the firmness come from the facts, not the adjectives.

A day-seven message that stays professional:

Hi Marcus, just following up on invoice #388 for $1,240, now 7 days overdue. If it has already gone through, ignore this. If not, here is the link: pay.sms365.com.au/m2Rd . Happy to sort out a payment plan if that helps, just reply here.

Notice the "just reply here". A dedicated two-way Australian number means the customer can answer the text and you see it, so the reminder becomes a conversation rather than a broadcast. Most late payers are not dodging you. They forgot, or they have a cash-flow week of their own. Giving them a way to say so keeps the money coming without burning the bridge. There is a full polite late payment reminder script if you want messages for each stage.

When they say "I will pay Friday"

This is the most common reply, and it is where most follow up falls apart. You say "great, thanks", you both move on, and Friday comes and goes. The fix is to write the promise down and follow up on it specifically. SMS365's AI assistant can record a promise to pay against the invoice when a customer replies with a date, so nothing depends on you remembering. Then the follow up references the promise, which is far harder to ignore than a generic reminder. There is more on this in how to follow up when a client says payment is coming.

Be honest about what a sent text does and does not do

A text is opened far more reliably than an email, but no SMS platform can promise a message was delivered to the handset. When SMS365 shows a message as "sent", it means the message was handed to the carrier. It only shows "delivered" when a real delivery receipt comes back. Anyone promising guaranteed delivery is guessing. For chasing invoices this is fine, because the open rates are high and you have a two-way number, so a customer who never got the message can tell you.

Stay on the right side of the rules

Reminders about a genuine invoice for work you did are transactional messages, not marketing, so they sit in a different category to promotional texts. Even so, good practice is to send from a recognisable number, keep the message about the transaction, and honour any request to stop. SMS365 keeps a working STOP and START on every number with an append-only consent record, so if someone opts out it is respected and logged. Keep your reminder messages strictly about the invoice and you have nothing to worry about.

Set it up once, then let it run

The businesses that get paid fastest are not chasing harder. They have a system that sends the right message at the right time without anyone lifting a finger. Connect your invoicing, write your four messages once, and let the schedule do the chasing. You get to spend your evening doing anything other than composing "just following up" for the third time.

If you are weighing up the cost of running this against the debtor days it saves you, the pricing page lays out the prepaid rates with no lock-in, so you can start small and see what it does to your cash flow before committing to anything.