Before You Text a Customer About a Late Invoice

A team we talked to recently used to text customers about overdue invoices through a free consumer messaging app. It worked. Invoices got paid. Then the app banned them for spam, and they stopped texting customers altogether.

They're not an edge case. Within the space of a few weeks, five different customers asked us the same question: can we text people about overdue invoices? Short answer, yes. The longer answer is about consent: who you're allowed to text, what counts as an opt-in, and what happens if you get it wrong. Those answers decide whether texting becomes your best collections channel or your next problem.

Everyone is already texting. That's the problem.

Here's what "SMS reminders" looks like in the wild right now, from recent customer calls. A law firm's AR lead texts overdue clients by hand, one at a time, after the email reminders go quiet. A retailer running payment plans texts from two store cell phones. A property manager chases a dozen delinquent renters from her own number every month. A field services company texts through its dispatch software, but only for service updates, because nobody's sure billing texts are allowed on it.

Everyone improvises because texting gets answers. You'll see a stat floating around that texts have a 98% open rate; nobody can trace where that number actually comes from, so we won't lean on it. What we can offer is what shows up in our own calls. One team's routine for a single failed payment was six emails before anyone picked up a phone. An AR lead told us certain clients only ever respond to texts, which is why she sends them by hand after the email reminders go quiet. And in payment disputes, the text log itself does work: "we texted you on this date" ends a lot of arguments. When you're the one waiting on the money, a channel people actually answer is the whole ballgame.

So keep texting. Just do the consent part properly, once, and then let the reminders run themselves.

The part that keeps companies out of trouble

Here's the sentence nobody wants to say out loud: most of the improvised invoice texting happening right now, including some of the setups described above, probably doesn't meet the consent bar. Nobody's being reckless; nobody told them there was a bar.

Text messaging has rules that email doesn't, and they're worth reading firsthand rather than taking our word for it. The federal law is the Telephone Consumer Protection Act, and the FCC's implementing rules live in 47 CFR § 64.1200. The short version: texting someone for business purposes requires their prior consent, the bar is higher for marketing texts than for transactional ones like an invoice reminder, and the penalties run $500 to $1,500 per text, not per campaign. Since April 2025, FCC rules also require honoring an opt-out made by any reasonable means within 10 business days.

The carriers enforce their own layer on top of the law. Business texting in the US runs through a registration system, and the industry's rules of the road are the CTIA Messaging Principles and Best Practices. Numbers that generate spam complaints get shut down regardless of what your lawyer thinks about your consent. That's the mechanism that got the free-app team banned.

The questions our customers actually asked, and the honest answers:

"Does the payment plan form we already use count as consent?" Probably not on its own. Consent needs to be specific: the customer agreed to receive text messages from you, about this kind of thing, at this number. A signature on a form that never mentions texting isn't that. If your existing agreement does mention SMS explicitly, you may be in better shape, but this is exactly the clause to run past your attorney rather than a billing company's blog post. We'll tell you how the mechanics work; what your documents cover is a legal read.

"Can we just text everyone and ask them to opt in?" No, and we get asked this a lot. The ask-for-permission text is itself a text you didn't have permission to send. Consent has to exist before the first message. The clean paths for existing customers: an email pointing them to a portal where they check the box themselves, or the box on an invoice or update-payment page they're already visiting.

"We already collected opt-ins somewhere else. Do customers have to opt in again?" No. If you have real consent captured in another system (a signed contract with an SMS clause, a field in your CRM or dispatch software), it can be imported. Nobody wants to make a thousand customers re-agree to something they already agreed to.

"What proof should we keep?" Where and when each customer opted in, and what they opted into. It matters in a dispute, and not only the legal kind. One customer told us the SMS log settles collections arguments by itself: "we texted you on this date" ends a lot of phone calls.

What the automated version looks like

Once consent is sorted, the texting part is genuinely the easy part. In ChargeOver, SMS reminders hang off the same schedule your email reminders already use. An invoice comes due, the customer gets a short text with a payment link. It goes past due, the past-due nudge goes out on whatever cadence you've set, day 3, day 7, whatever matches how you collect.

A lot of the details exist because customers asked for them. Opt-ins can happen three ways: new customers check a box on your signup form, existing ones check it in the portal, and consent you've already collected somewhere else comes in through the API or a spreadsheet. Once someone's opted in, they get the text instead of a duplicate email for those events, so nobody gets nagged twice for the same invoice. The messages stay short on purpose: a reminder and a payment link, not a letter. And every text is logged per customer, which is the paper trail for the dispute question above.

The part nobody has to do anymore: being the person who remembers. The law firm's AR lead was manually deciding, client by client, month by month, who needed a text. That judgment call is now a schedule.

The honest fine print

Texting costs money in a way email doesn't. There are usage-based fees per message, and the right setup depends on your volume, so talk to support before you turn it on and they'll walk you through what it'll actually run you. Getting your business registered for texting is also a real step, not a checkbox: there's a form about your business and your messages, a verification wait measured in days, and it's not optional. Plan for it the way you'd plan for any go-live. Neither is a reason to keep texting from a store cell phone. Both are worth knowing before you start.

Turning it on

Already a ChargeOver customer? Setup lives in the SMS reminders help doc, and support will tell you what your volume will actually cost before you commit to anything. The consent questions are the ones to bring; we've heard them all.

Not a customer, and you got this far because someone at your company is texting overdue clients from a personal phone? That's a fixable problem, and the fix is smaller than it sounds: a consent checkbox where customers already sign up or pay, the registration form above, and a reminder schedule you set once. Book a demo and we'll walk the whole path with your own invoices: capturing consent, setting the reminder schedule, and the logs that prove you did it right.