Oil changes at real gas stations don't guarantee things will go well. Years ago, I had our local Mobil station change the oil in my wife's car. They said the head was stripped on the original drain plug and installed a universal rubber plug that would be replaced with the proper one at the next oil change. Next day, my wife called from her office to say there was a puddle of oil under her car. The plug popped out. I called the Mobil station and was promptly disconnected, so I called the Chevy (sorry if it's a dirty word!....) dealer and had them tow the car to their shop. I had to leave work in Manhattan, go home to Staten Island, and drive to her office in Northern NJ to get her after work.
Luckily there was no engine damage; the dealer installed a new plug and refilled the oil. The gas station guy refused to pay the bill, so I contacted Mobil directly (their main office was around the corner from where I worked so I went there in person). I explained that I wanted the dealer's bill reimbursed or I'd take legal action. A week later I had a check from Mobil.