1998 Mercury Tracer Timing belt repair gone bad

Hello. I have a 98 mercury tracer with a 2.0 spi engine. Recently my car had broke down. It just lost power, the lights worked and everything. Needless to say it was the timing belt. Well the mechanics that did the work replaced the timing belt but they messed my car up big time. They broke the plastic housing on the top right and on the bottom left. Aside from that the car is now making a constant rattling noise and when I accelerate it goes to 4grand and shifts over about 15 mph. Which doesn't feel right, it takes a whole city block for it to accelerate up to 25mph. Do you guys have any ideas on what I could do to make the noise go away and make the car run normal? And is it possible that the tensioner or some other component that makes the timing belt work be the source of it?