You probably fried it and will have to buy a new one. If you gave it more volt's than it was looking for, lots of internal stuff probably went zzzzzzzzzap. If it didn't zap, it would work.
EDIT: If you are an electronics wiz and great at soldering, you may be able to open it up, possible desolder and replace a fuse and or capacitors, and many other components. Cheap boxes like that probably don't bother with inline fuses.