Belly Cover not replaced

I have my car serviced at Audi East Rand, after my last service i noticed an oil leak on the vehicle, on inspection to check were the leak is coming from i noticed that the belly cover of the vehicle is missing. I reported it to the Service adviser Chris who in tern notified the the Workshop Manager about the missing cover, all they say is that its not there problem, does this mean that every time i pick up my vehicle at a reputable dealer i have to get under my vehicle and check that everything has been replaced and in place, if it was not for the leak that i picked up i would never have known of the cover that was not replaced, it is now 3 weeks since i have reported this to the dealer as well as Audi SA and it still has not been resolved.