Duplicating of license discs

After my car was taken in for it's first service, I had a suspicion that my license disc had been fiddled with. Upon investigating, I realised that it had actually been removed and glued back on. I know it is my responsibility to make sure that all valuable goods have been taken out the car, is it also my responsibility to make sure that the license disc is securely placed on the windscreen? I think it is pretty careless of Hyundai Sandton to dismiss this and hang up on me when I was enquiring about this issue. For all I know a duplicate vehicle is somewhere out there with my details. For all I know Hyundai Sandton is hiring ********* to service my car, *****ing parts, and copying our license discs. Cloning is a problem is SA and I think it's only far that car dealers take this seriously.