Will NEVER use this company again!! My 2012 Nissan...

Will NEVER use this company again!! My 2012 Nissan Xterra quit running in the middle of I95S in Palm Beach, FL on Sunday around 5 p.m. There weren't a lot of options where to tow it and we had to be at my son's college orientation early Monday morning. Took it to Pep Boys at 3189 Northlake Blvd and they determined it needed an alternator/battery but we had to leave it. The manager showed me an estimate for $700 which was with military discount which I thought was high but I was desperate to get back on the road. The got us a Lfyt ride to get a rental. Today, we went to pick it up and the same guy said my bill was $990 which again included military discount. I complained and he knocked it down to $880.42 and said the estimate he showed me was only for the alternator. I had no choice but to pay it to get my vehicle. This is RIDICULOUS! Horrible customer service!