Top 5 Mistakes Subcontractors Make When Chasing Unpaid Invoices

Chasing unpaid invoices is stressful, time-consuming, and often ineffective when done the wrong way. Many subcontractors make avoidable mistakes that weaken their position and delay payment — sometimes permanently. Here are the five most common mistakes subcontractors make when chasing unpaid invoices, and how to avoid them.

Mistake 1: Waiting Too Long

The most damaging mistake subcontractors make is simply waiting too long before taking formal action. It’s understandable — no one wants to damage a business relationship, and it’s tempting to believe a head contractor when they say “payment is coming.” But waiting too long has real legal consequences.

Security of Payment laws have time limits. In Victoria, you may have as little as 3 months from the reference date to serve a valid payment claim. In WA, the window is 28 days. Miss these deadlines and you lose your SOP rights entirely.

Fix: Don’t wait. Serve a formal payment claim as soon as an invoice becomes overdue. You can still negotiate — but you want your legal rights preserved while you do.

Mistake 2: Using Informal Channels Only

Sending emails saying “just following up on our invoice” and making phone calls does not put any legal pressure on the head contractor. They can ignore it indefinitely. Many subcontractors spend weeks or months on informal follow-up that produces nothing, while their legal rights tick down.

Fix: Serve a formal SOP payment claim. This is not a polite follow-up — it’s a legal document with consequences. Head contractors respond very differently to a payment claim than to a reminder email.

Mistake 3: Accepting Partial Payment as Full Settlement

When a head contractor offers a partial payment, the temptation is to accept it out of relief. But if you accept a partial payment in a way that implies it’s a full settlement — particularly if you sign anything saying so — you may have given up your right to claim the balance.

Fix: If you accept partial payment, make it clear in writing that you are accepting it “on account” and that the balance remains owed. Never sign documents marked “payment in full” without legal advice.

Mistake 4: Not Documenting Variations

Variations are the most commonly disputed invoice item. Subcontractors who perform additional work without documented instructions — or who fail to follow up verbal instructions with written confirmation — often find their variation claims denied.

Fix: After every verbal instruction for additional work, send an email or text confirming what was instructed, by whom, and when. Photos of additional work and site diary entries help too. This evidence is invaluable in adjudication.

Mistake 5: Trying to Handle It Yourself Without Understanding the Law

SOP adjudication is a legal process with specific requirements. Payment claims must be correctly prepared. Service must be done the right way. Adjudication applications must include the right evidence, presented correctly. Subcontractors who try to navigate this without help sometimes make procedural errors that invalidate their claim or weaken their position in adjudication.

Fix: Use PayClaim. We handle the entire SOP process — payment claim preparation, service, adjudication management — for a flat fee. You don’t need a lawyer, but you do need someone who understands the process. That’s us.

Get It Right From the Start

Chasing unpaid invoices doesn’t have to be a long, exhausting process. When done right — using the SOP Act, serving a compliant payment claim, and being ready to apply for adjudication — most disputes resolve within 10–20 business days. PayClaim makes it fast, affordable, and effective. Start your free claim today.

Owed money? You can start your Letter of Demand here — see the whole letter free, then a flat $69 to issue it. PayClaim is not a law firm; payment outcomes are not guaranteed.