Shady Mechanic

I took my car to a mechanic last week when the car just started dying while on the freeway and it turned out to be a bad fuel pump that needed replaced. Well, after they fixed the fuel pump they told me that the alternator needed replaced too. I thought that was a little too coincidental that the alternator would go out at the same time as the fuel pump so I told the mechanic that I would pick up the car and have another mechanic fix it. Well, to make a long story short, the shop my car was at called me and told me that our battery got stolen and that he had to replace it. After I picked up my car and took it to Autozone, Autozone said that the battery was 8 years old and that the alternator was fine. So..... basically I am filing a complaint with the Better Business Bureau. This shop I took my car to was really shady and apparently they have a history of stealing car parts and replacing it with older ones...