Pontiac Repair: OXYGEN SENSORS, oxygen sensors, exhaust shop

Question
HI
I had my car in a shop replacing the oxygen sensors they said they had to break the sensor out because they had problems getting it out. they said they would guarantee the work because they had to retread it it lasted 1 week. i know this is a tough question to answer without looking at the car should  i just get a whole new exhaust so the sensor with thread in right.   my car is a 99 grand am 4 cylinder  

Answer
Hi
Depending on which sensor it was (front or rear) I would say yes for the front sensor (That'll need an exhaust Manifold). You should be able to get one fairly inexpensive at a local Salvage/Used parts yard.
The rear they should be able to repair eaiser, if not they should be able to make you a new pipe, if they a good exhaust shop.
I would though, see what type of "help" they going to give you, you SHOULD not bear the entire cost alone.
I Hope this helps
Good Luck
Pawl