A client who hasn't paid is rarely a bad client. Usually it's a misfiled invoice, an approver on vacation, or an email that landed in spam. The difference between collecting in week two and collecting in month four is rarely the client: it's whether you had a collection calendar or improvised every time.
What the delay actually costs you
In the Federal Reserve's Small Business Credit Survey, published March 3, 2026, 56% of firms that sought financing did so to meet operating expenses. When your invoices arrive late, you end up covering that gap with debt that charges interest right on schedule.
Before the first message, check your own invoice
Half the collections that stall don't stall because of the client. Before writing, confirm four things: the invoice went to the right email, the due date is written as an actual date and not as "Net 30," the client's purchase order number appears, and the description lets someone on their side approve it without calling you.
If any of the four is missing, don't chase: resend the corrected invoice the same day and start the calendar from there. Chasing an invoice your client couldn't process puts you in a weak position and speeds up nothing.
The calendar: six contacts in 45 days
The rule is to escalate slowly and skip no steps. Each message assumes the previous one never arrived, not that the client is dodging you. And everything in writing, even when you call: after every phone call, a two-line email summarizing what was agreed.
Day 1 after the due date — the neutral reminder
"Hi [name], I'm writing about invoice [number] for [amount], which came due yesterday. I'm attaching it again in case it got lost. Can you confirm whether it's in the payment queue? Thanks."
No apologies, no "sorry to bother you." You're collecting for work delivered, not asking for a favor.
Day 3 — confirm it reached the approver
"[Name], did invoice [number] reach whoever approves payments? If you send me their email I'll forward it directly and stop taking up your time." This message usually surfaces the real problem: the person who hired you isn't the person who pays, and nobody made the connection.
Day 8 — the phone call
Call. A three-minute call resolves more than six emails. The goal isn't pressure, it's leaving with a specific date: "What day is the payment scheduled for?" If the answer is vague, propose a date yourself and ask them to confirm it by email.
Day 15 — the interest notice
"Attached is the statement for invoice [number], 15 days past due. Starting [date] I'll begin applying the late interest stated on the invoice. I'd rather not: if you confirm a payment date this week, we leave it there." Send this only if your invoice or contract already said interest would apply.
Day 30 — the formal letter
Change both tone and format: a letter, not another email. Date, amount, invoice number, a summary of the previous contacts with their dates, and a specific deadline. Close with what happens if there's no payment. This letter is also your evidence if the case reaches court.
Day 45 — decide
At 45 days you have three paths: accept a written payment plan, send it to collections, or sue. What isn't a path is sending the same reminder every week for six months.
What interest you can charge in Florida
If your invoice says nothing about interest, Florida Statute 687.01 applies: the rate is the one the state sets. For the quarter that began July 1, 2026, the Florida Department of Financial Services set it at 8.06% per year, down from 8.25% the previous quarter.
If you'd rather set your own rate, there's a ceiling. Statute 687.03 treats anything above 18% simple interest per year as usury on obligations up to $500,000. The classic "1.5% per month" many people print on invoices is exactly that 18% a year: it sits at the limit, not below it.
And the part that matters most: interest is collectible if it was agreed beforehand. Announcing it after the invoice is already late rarely holds up. Put it on the invoice from the first job, not once there's a problem.
What you can't do while collecting
If your client is a consumer rather than a business, Florida Statute 559.72 reaches you even as the original creditor, not just agencies. It bars communicating between 9:00 p.m. and 8:00 a.m. in the debtor's time zone, using abusive language, and contacting at a frequency that can reasonably be expected to harass.
It also bars communicating with the debtor's employer before you have a final judgment, absent written permission, and disclosing the debt to third parties without a legitimate business need. Translated: don't post about it, don't tell the spouse, don't call fifteen times.
When the script runs out: small claims
In Florida, small claims court handles demands up to $8,000, exclusive of costs, interest and attorneys' fees, under Small Claims Rule 7.010(b) in effect as of July 1, 2026. You don't need a lawyer to file.
The filing fee is set by Statute 34.041 and rises in brackets: $50 for claims under $100, $75 up to $500, $170 up to $2,500, and $295 from there to $15,000. On a $3,000 invoice, filing costs $295 — nearly 10%, but far less than writing off the whole thing.
Don't let the clock run out
Statute 95.11 gives you five years to sue on a written contract, and only four when the agreement was verbal or is an open account. That's another reason every job should have something signed, even if it's just an email with the scope and price accepted in writing.
Three mistakes that stretch the delay
- Waiting until it "looks bad." Day 1 is the best day to write. The longer you wait, the more awkward the message becomes.
- Delivering new work anyway. If an invoice is past due, the next job pauses. It sounds harsh, and it's what keeps the hole from doubling.
- Collecting only over WhatsApp. It's fine for reminders, not as orderly evidence. The email with the invoice attached should always exist.
A well-run collection doesn't damage the relationship, it organizes it. Clients who leave because you collected firmly are usually the ones who never planned to pay in full.
This is general information, not legal or tax advice. The rules cited are Florida's and may not apply in your state or country. Consult an attorney about your specific situation.