95 Dodge Avenger.

So I took my car to a local shop to fix the housing for the transmission and transaxel. When I got the car back it ran like poorly and wouldnt shift right and had no power. It also knocked real bad from the top of the engine. Before we took it to them it ran great and had no problems. We finally got it back to my house and we gave it a tune up. That help a little bit. We were driving it after the tune up and it totally shut down on the road and wouldnt start and engine was locked up. Upon further investigation the Timing Belt had slipped somehow and the valve cylinder and piston head were damaged. I think that when they did the work on it they rotated the engine the wrong way to take out the bolts in the torque converter. If you turn the engine backwards will the timeing belt slip causing the cams to be out of line with the crank shaft? I have heard on Dodge engines that if you rotate the engine backward it can cause the timing belt to slip. Could this be why it ran like bad after I got it back from the shop and was knocking loudly from the top of the engine? If you could give me any help that would be great.
Thanks