Drew, thank you. I have already given the PM notice to terminate our business. This is one of several mistakes, miscommunications, etc. over the last 10 years. The way the PM contract is set up made things difficult to cut ties. Discussing the situation with my other property manager (different state), friends who own and manage properties, and several other vendors who are install A/C (including a personal friend who owns an A/C company), they all felt was offer was more than fair.
Tom, thank you. Yes, I have a lawyer. The vendor didn't rely on someone's authority, but their own. - it was rejected by me and the PM company, but they did the work anyways.
Let me add - after receiving the initial A/C quote, I rejected it, and told the PM to no longer use that Maintenance Company for anything. The A/C fiasco confirmed my suspicion, the Maintenance Company was finding other licensed companies to do the work and then "up charge" me. My Bill from the Maintenance Company was $7450, the bill from the actual vendor to the Maintenance Company was $6200. My PM should be going to the third party vendor directly. However, during our "negotiations" the PM told me the actual cost was $4750 (Note - after the fact I received a today quote for $4200 - this was from a previous vendor who had worked on the A/C and was familiar with it).