Those lights are supposed to be a sealed assembly, so if there’s condensation then you need to replace the assembly. If the shop didn’t replace the assembly themselves then they’re never going to accept responsibility for an original post-collision taillight assembly.

It’s worth looking up the cost of a replacement assembly part and watching a video on how to replace before you decide to go back to the shop though. I don’t know about your car specifically, you’ll have to do the research, but on most cars I’ve worked on this is an easy repair. Good luck

Cheap bluetooth obd2 scanner. But yeah, I’ve been trying to keep my Amazon spending to a minimum. I’ll try to buy from anywhere else first