We are a commercial plumbing company. We worked with a GC on a number of projects a couple of years ago. There are about 4 jobs that have not been paid by this contractor dating back to 2017. To date, the contractor has not paid the balances due on these jobs. We also had 3 jobs that were a little more problematic, dating back to the fall of 2018. Other than one of those job (on which we only completed 1 of 3 phases), we completed the other 2 through final inspection. We attempted for some time to collect on this work. Finally, months after the fact, the GC is saying that he had additional costs on these jobs, and will not be paying for them; furthermore, he is attempting to hold the monies owed on the 2017 work (completed satisfactorily) against his "additional costs" on the 2018 work. I never received, and have still not received, any sort of deductive change order or accounting from the GC regarding the 2018 work that he is alleging had additional costs. I do not believe that is legal in Georgia to hold monies on one contract for an issue on a different contract. Furthermore, it seems that there must be some mechanism or process for applying "additional" costs (via a deductive change order) to monies owed from a GC to a subcontractor. Can you give me some insight on this, and whether or not what the GC is attempting to do is legally allowable? THank you for your time