How to Bill When the Payer Is Not the Customer
When a third party pays — a law firm, property manager, insurer, servicer, or AMC — get the payer's reference number, approval limit, and billing contact in writing before you start work, invoice in the format their system codes against, and never let the person receiving the service authorize charges the payer hasn't approved. The person on site is not the person who pays, and every unpaid third-party invoice traces back to skipping one of those steps at intake.
Establish four things at intake
- The payer’s reference number — case, matter, order, claim, work order, PO
- The approval limit — what you can perform without a new authorization
- The billing contact — a named person or an AP address, not the field contact
- The terms — net 15, 30, 60, and what triggers the clock
Missing any one of these turns a completed job into a receivable nobody owns.
Invoice in their format, not yours
| They use | You write |
|---|---|
| Case/matter number | On the header, every invoice |
| Allowable line codes | Their line names, exactly |
| Store or property ID | Identified per line |
| PO numbers | Referenced, not omitted |
Matching the payer’s format is worth more than any collections effort afterward. An invoice their system can code goes into a payment run; one it can’t goes into a queue and just sits there.
The person on site cannot authorize spend
A tenant, borrower, occupant, or patient asking for extra work is spending someone else’s money, and that someone else will decline it later.
Quote to the payer, get it in writing, then do the work.
Keep a direct-pay segment alive
Third-party channels give you volume without marketing, but they also set your price, your format, and your payment speed.
So always keep some clients who pay you by card on the day — realtors, private clients, homeowners, small businesses. That segment is what funds the week while the big invoices are still maturing.
Bill the day it’s done
Long terms start when you invoice, not when you finish. A three-day delay in sending is three days tacked onto net 60 — probably the cheapest cash-flow improvement available to anyone doing third-party work.
Frequently asked questions
Who do I chase when an invoice goes unpaid?
The billing contact you established at intake — never the person who received the service. They have no authority, no visibility into the payment queue, and putting them in the middle damages the relationship that generated the work.
What if the on-site person asks for extra work?
Quote it to the payer and get approval first. A tenant, borrower, or occupant asking you to do more is asking with money that isn't theirs — and the payer will decline it after the fact every time.
How do I handle long net terms?
Price them in, invoice the day the work is complete, and keep a fast-paying direct-client segment alongside the slow one. Terms you agreed to aren't a collections problem; they're a working-capital fact you plan around.
Should I take third-party work at all?
Yes — it's volume you don't have to market for. Just never let it become your only channel. A book of business that's 100% one servicer or AMC means someone else controls both your price and your cash flow.