Hi we are HVAC contractors in Texas. In our attempt to collect final payment on a contract, the general contractor is claiming their was an issue with the job and they had to call another HVAC contractor to fix the job. They are trying to deduct it from the amount owed? They refuse to pay the rush fee for some of the materials and they still owe us funds from the original contact but refuse to pay it.I want to just get the money owed to us? Can they do this? Also in order to get one of my payments they forced me to sign a 1 year letter of warranty. Since they are not paying me am I obligated to keep going out to the job site every time they say it's hot? If I don't go anymore can they charge me back?