After months of trying finally got a response from Mavic about my Cosmic wheels. Unfortunately they can't supply spare hub covers so I'm going to get some custom made. It's a shame Mavic aren't like Campagnolo as I'm sure they would have spares for older parts. Modern parts are disposable not like older parts which were made to last. At least after this experience I won't be buying Cosmics for my new road bike, I quite like Fast Forward and there replacement policy.