Business ProfileforMaster Buick-GMC

This was my first and LAST time servicing my car here at Master Buick GMC on Washington rd. I only came here because the Cadillac dealership downtown closed. I was warned by an employee that works at this location (after I had already dropped my car off) that customers receive different prices and some customers are over charged for services all the time by a particular person and that the owner is unaware of this activity. This person told me if they had of known or seen me before hand they would have recommended not having my car serviced here. On 17Sep I was told that it would cost $518.86 for parts and labor for the 100,000 mile maintenance plus $140 for the diagnostic test for my check engine light which also was affecting my heat and I was told that if I decided to let them fix whatever the problem the diagnostic test found, the $140 for the diagnostic test would be deducted from the price. I signed the invoice sheet agreement for the work to be performed and price $518.86 to be paid plus taxes on 17Sep. On 20Sep I was told that the diagnostic test code and message said "P00B7 engine coolant flow insufficient and that they recommend starting with replacing the thermostat and then retesting and it would cost $950 for parts and labor plus" I would still have to pay the $140 diagnostic test. When I told him that I was told the week before that the $140 would be deducted from the cost to fix the problem if I let them fix it, he then says, well since they told you that. I told him not to fix it. Because after I called around to two different Cadillac/sister GMC dealerships and was told no more than $437.38 for parts and labor to replace the thermostat, I realized that it was overpriced . When I arrive to the dealership that afternoon to pay and pickup my car, my total that I signed and agreed to on the invoice for my 100,000 mile maintenance on 17 Sep went from $518.86 total to $702.47 ($183.61 more) just for the maintenance. The total with the diagnostic test included was $842.47. My total for the diagnostic test plus the maintenance should have been $682. 57 not $842.47. I also questioned why was I told over the phone earlier that afternoon that it will cost me $950 to replace my thermostat when it clearly says and is printed on the receipt/invoice in front of me that it is "$630 to replace thermostat but customer declined." After questioning that total, I was then told that "the total was $950 I lowered the price to $630 after I hung up the phone with you". My check engine light went off and my heat started back blowing warm air 3 days after getting my car back. I still took my car to another Cadillac GMC dealership that next week to "replace the thermostat" but was told that the code on the sheet given to me from the other GMC was not the right code for a thermostat/"P00B7 engine coolant flow insufficient" and did not recommend replacing my thermostat/spending $437 to do so if that's not the problem and that the coolant flush could have inadvertently dislodged some possible slug that could have been blocking the coolant flow and triggering the check engine light to come on. Thankfully to say my car has been running fine and the check engine light never came back on and my heat is working. Also to add, when I arrived on 20Sep to pay, the invoice agreement that I signed on 17Sep with the correct total of $518.86 was no longer in my chart/folder with my other signed paper and key fob. I had the initial invoice reprinted. I was told that the parts department over charged me. So the price was adjusted by decreasing the price of some items on the invoice sheet, deleted two items/jobs and gave me a "misc $50 discount for my time dealing with the mix-up."