Disappointed last time they said oil change is not...

Disappointed last time they said oil change is not required at this time but they charged for oil change, and I asked them about the charge and they took my car for oil change.

Today I came again for oil change had my appointment scheduled at 11:45 am waiting for 2 hours they have not started service yet, 2 cars came 12:30 they completed oil change for them, I asked the guy and he said those cars are new, and they are not allowed to make them wait