Missing car parts

I'm worried with this dealer, Ford Lazarus in centurion as I took my car in for service and to my surprise my engine cover went missing and is nowhere to be found. I raised this with the dealer but they keep on covering up claiming that my car originally did not come with the engine cover. Never the less, the fact remains that my car had a cover before going into dealer and now is missing. I'll like customers to be away of this kind of behavior and consider other dealers that will treat their motor vehicles with respect in making sure that customers get their vehicles same as before the service. It is totally unacceptable to take in your car for service and other parts goes missing and no one is accountable or takes responsibility.