Builder terminates then wants to be reimbursed for work already performed

I am a small plumbing company in southcarolina,the problem is this,ON each phase of a house I get paid after it has been inspected,1500.00 for the 1st rough,1500.00 for the 2nd rough and 445.00 for the fixture set,I recieved the first 2 payments as due me,during the completion of the last phase the builder "said he would get someone else(verbal)now the builder is threating me with legal action if I do not PAY HIM 667.00,he claims he overpaid me.Can he do this?I only recieved the amount we agreed upon.
hopenewk in SC

I am a law school graduate. What I offer is mere information, not to be construed as forming an attorney client relationship.

The professionals on this board need to know a little more about the subcontract you had with him.

You get paid by what you have done and by each phase if that is how your contract goes.

You don't owe this builder anything for his change of mind.