Cellini Voyager 4 wheel case combination faulty

The store attendant set my pin for me for my 3 number combination lock on a brand new roller carry on bag. I tested it and it worked. I packed my things into it and checked it into the baggage hold. When I got to my destination the combination ,which I know is correct, did not work. I will need to break open my bag to get to the contents thereby losing my 3 year warantee. I feel very disappointed and cheated.