Began running poorly & the ac stop working at the same time.

No telling what the source is; Did you say you couldn't fix it right now, so they tried to help you out. Why would anyone allow someone to ' RIGGGGGG' their car I will never know. Take to someone else who knows what they're doing and fix what is wrong correctly, no cutting corners. I'm sure you allowed it or you would have taken it back to them and demanded they fix all the problems.