I have been having a hard time finding out what is wrong with my AC. Last fall it was working fine. This year it was only blowing hot air. Took in to get it charged. Picked it up still blowing hot air. I took it to another shop they said it had too much pressure and needed to be evacuated and recharged. I did that. Still hot air. The shop then said that the expansion valve needed replaced. I went today to pick it up. It now blows cool air and not even very cool air. They now say that the compressor probably isn't working as well as it should be so I need to replace it. I'm over a grand in AC repairs. Both shops told me the compressor was fine. Now they say that it is the problem. Does this information sound right?