Gmc service near Houston, TX

Quoted the price of $200 plus tax over the phone and was later told the charge was $276 plus tax due to the programming of convertible top. I expressed to the mechanic, who I assume was the owner, the price I was told and I would like it to be honored. I was then told by the mechanic I was quoted $212.50 plus tax over the phone which I expressed was not what the lady told me. In addition to not being charged the right amount I asked the receptionist if it’s possible for the mechanic put the battery housing cover back on the battery once complete since an O’Rileys worker removed it to inspect the battery. She stated it wasn’t a problem which I later discovered it was not done. I’m extremely dissatisfied with the level of service I was provided given it was my first time having maintenance done at the shop.