Car wont shift into reverse, 1st and 2nd gear not working properly
 

So I have a 99 jetta, manual. I brought my car into American to get a indash deck installed today. My car was driving fine all day and week, when I went in to get my car it started up fine and everything. Then when I went to shift into reverse I realized that my shifter was extremely loose, and when I put it into reverse and started to go I was moving forward..... and when I put it into first gear it feels like it is in third and when in second feels like fourth. Does anyone know what might have happened to my car? Also American is saying they didnt do anything to my car to cause this problem. Do you really believe them??

Car wont shift into reverse, 1st and 2nd gear not working properly
 

sounds like a broken shift fork. It is pretty common and can happen at any time. the end of the shift fork is just tack welded on the shaft. I would just replace the shift fork if the trans worked good before you had the problem. Probably cost the same as a used trans that would have the same problem eventually