2006 CHEVY Cobalt repaired.

They charged me $538.62 to fix my daughter can but did not. I had to take it elsewhere to get it fixed. Her car broke down on Interstate spur 565 and I picked Superior Auto Care out because it was close and I thought at the time would cost too much to tow home. After charging me $84.96 to find the problem, they still were not sure but said changing the Oxygen sensor and giving it a tune up should fix it. The cost was $538.62. After they did this, they called to tell me it was something else and would cost (from memory) around $200 to $300 to fix the real problem. I took the car elsewhere and got it fixed for $100. I feel I was took advantage of because I was from out of the area. If I was not took advantage of, then they seem to not have the skill to diagnose car problems.