Axle issue

My sons just bought car from two mechanics who told us it needed new transmission and clutch. All it did before they worked on it was made a little winding noise in reverse and a couple times when in first gear it spitted out of gear they charged us $2.000.00. Today we get a block away my son went to turn left and it made a piping knocking sound, also the steering wheel like whipped hard so we took the car right back they test drove it and noise was loader and more, but they said oh the car was in an accident previously so it must of messed up the axel, but they do not want to take any respond ability. What do you think and what can we do? It took every penny we had and just purchased the car for $6,500.00 a week in a half ago and did it not make any kind of noises.