This weekend my friends and I were bumping my subs a little loud with the car off and while the subs were up loud I flicked the bass boost switch and soon after that they stopped working (amp was hot and thats pretty usual for it), I took the amp to this crappy car audio place I got them from and they say the sub isn't blown and that it isn't the fuse or anything. The amp has power but this green light that is titled power isn't on and it usually is. I have had them for a few months and the place I got them from is gonna charge me 40 dollars to look at it and I don't have the receipt to get it replaced or returned. Any clues or anything (also i'm new to car audio so I have no idea how to fix it or what wire ground is or whatever)

Thanks in advance
its not the fuse because the amp has power but it will not bump the subs (subs arent blown) and i dont know how to check my ground or what that is