Omnico not replacing broken Gopro mount

I purchased a handlebar bracket for a Gopro from Cape Union Mart Rosebank. Unfortunately it developed a crack and was about to break. I took it back to Cape Union Mart (with the till slip). I was informed by Cape Union Mart that the warranty period of 1 year had expired and that the supplier (Omnico) will not be sending me a replacement one. I am not happy with both Cape Union Mart and the Gopro supplier (Omnico). The bracket should not break as the design and/or workmanship was defective.