Pep Boys

I feel really pissed, after taking my car to pep boys on Friday. They ask 107$ for diagnostic. And they said they''ll call me on the next day which is Saturday for the next step, which is supposed to be the result of the diagnostic and the cost to get it fixed. I was so tired waiting for their call, nobody called me, finally at the end of the day, I called them they told me the car doesn't really have a major problem but..... something with the tenser. they said including check up, that'll cost 901$. I was waiting for the final call to go get the car and pay them. they never called me, I call them on Tuesday, now they told me, I have to tow the car the Mercedes benz dealership, cause the ECM is not transmitting signal to the ... whatever. I was like....What....!
last Saturday after diagnostic that's not what you told me. if after opening the car, your mechanic put more damage in my car instead of fixing it, it's gonna be a real issue. actually they still have my car, the guy said he has to talk to the manager and call me. hopefully they call me. if Not.........!!! If you can't work on these type of cars, just be honest say you don't.