A couple things going on here Ron..
The problems that developed AFTER you serviced the property... were they additional problems or problems from he original service ??
New problems would be a new service call, and problems from the original call if your fault needed to be dealt with immediately, instead of an extended call back period.
If you have a service policy set up to address these issues, then if you follow it, the client has no basis for protest or non payment. Now some clients are pretty sharp, and he probably saw this as a chance to welch on the payment for the original service, and there is probably some reason for a price ADJUSTMENT, not a write off.
Now this does say something about the clients character, so maybe he's not such a great person if you guys were not able to work this out.
Now he has sold the subject property, so your chance for a lien is gone, and usually liens , at least in Oregon are subject to a bit of pre job paperwork and precedence work. You may still have recourse against him in small claims court, but the minute he brings up , twists and distorts the service problem and issue, most SC judges would find for him.
I would offer a price adjustment in this case right now, a fairly significant one, but he does own you some money, because he did receive value from a portion of the service. I would find out what he paid another company to "correct" whatever problem it was, and then bill him for the rest of the work you successfully did.
In our larger estimates and even service calls, we have the work estimated out on an internal estimate sheet, that allows us to assign a value to every line item in the project.
This way we can show what the client has received value for and what is in dispute. Our contracts are worded such that a client CANNOT withhold the ENTIRE amount when only a portion of the service is in dispute.
I think if you offer a credit for th disputed or services by others, then bill for the balance, you have demonstrated good faith in trying to solve the problem, and would prevail in SC court for the reduced balance.
Outside of that, Rick knows some Jersey boys that might help you out...
