How to check or what are the symptons when youre timing belt was installed wrong?

I have a 99 Hyundai Sonata and the timing slipped, so it set in my driveway for about 7 months. With a 4 cyl manuel, the engine is a interferrence engine, when it is easy to mess up the engine. So I had the timing and the other belt to the timing replaced. On my way home the car went out, ecu fuse. Took it back to the shop. The guy said now its blowing a 30 amp fuse when it is supposed to take a 20 amp. WHY DO WE HAVE FUSES? He thinks I need a new computer for 400 dollars. I towed it home. When the car starts its rough, hits hards and I can here a tapping clicking noise thats constant, it sounds like the backside of the head. like maybe a valve. Is that what a valve sounds like when it is hitting. Is the timing not put on right that is making then engine run bad, which blows the ecu? Do u think the mech. knew what he was doing? How do I check the timing? Do u set the timing? Do u reset the comp.? He didn't do a diagnosis on the comp? Will it tell u if the ecu is bad? My O2 sen. bad