Bought a OEM Mercedes fuel cap, first time I put it on it would not unlock, it's defective sent proof to the company that it was defective. They told me to go to a Loker Mercedes Benz dealer and get them to warranty their part in line I had already gone to the Mercedes dealer and bought another part because I needed a gas cap that worked
plus the local dealers are not gonna warranty somebody else's supply
The supplier does not stand behind the products they sell