Stealing at a car wash & unprofessional handling of complaints

Took a for car wash this morning, next thing the manager tells us it wasn't there from the beginning, without 3ven investigating or saying this is our customer complaints procedure. Simple Question is, if that was the case, how come the place where is went out was not cleaned by your staff, it was still dirty. Then he tells us maybe it fell off whilst driving due to portholes. We live front opposite the mall are there any portholes. It is so annoying to be given such disrespectful and uncaring service. Your people are thieves. We've had this car for 10 years, if this was loose like you suggest why are there scratches around the cap, to show that it was taken out