Frame failure sudden death?
If an aluminium frame has to be bent back into alignment, it's trashed. Aluminium cannot be deformed without causing weakness in the material. 

If the bicycle repair shop literally hit the seat stays with a hammer near the dropouts to straighten the frame is probably weakened in those areas and is very likely unsafe. I personally would not ride that frame.

The bicycle repair shop should have told you the frame was un-repairable and not replaced the fork. Maybe they wanted to make some money of a repair job but I can't believe they passed up an opportunity to sell you a new bike.