It makes no sense,
the speakers would simply be out of phase, less bass most noticable, but connecting speaker wires reversed, at the amp or at the speakers should not damage the amp.
Amp repair
I have a Verastarr SSA-64 which has served me well until I crossed the cables on the speaker posts. I have tried to find someone locally to repair, but not having any luck. I have contacted Verastarr but they are not able to repair. I am looking for any suggestions in the central PA, Philadelphia, Delaware or Maryland area. I would prefer to take it in personally instead of shipping. Thanks in advance.