gas gauge doesn't work anymore

I just recently had some work done on my 1998 gmc jimmy, and when i got my truck back the gas guage no longer worked in it. I need to know how to fix this problem. I don't want to become stranded somewhere from running out of gas. The parts that were put on my truck were buschings, idler arms, pitman arms, rotors, brakes, basically a new front end. and something called a punkin? I need to know how to fix this problem....can someone please help me out....i have had this jimmy for less than a month now and its been in the shop twice so far....thanks , Donna

Sending unit has failed or the ground wire for it needs to be cleaned and reattached.

Take it back to where the work was done and tell them what happened. They might have broke a wire or something.