This is pathetic

To whom this may concern. On the 15th November 2014 I upgraded my contract to a Anytime 100 with a Sony Z3 compact,the deal was R399 per month at the somerset west mall branch. The consultant could not do it from his side because he could find the code for sony z3 compact so he phoned and asked them to do it over the phone which they did.The 1st bill was in December I paid roundabout R615 including the fees if I substract the fees I paid R499 for the contract. From December 2014 till May 2015 I paid about R499 every month. From June 2015 onwards up until now I paid R 509 every month. I enquired a couple of times in-store why is my bill so much.They ensured me everything is right its suppose to be that amount. I went to somerset west mall again on Saturday the consultant that did the upgrade for me and he found out they put in the wrong code.I'm being billed for a Sony Z3 and not a Sony Z3 compact. So for the last 17 months I've been billed for something I don't have.This is not what I signed up for. this is breach of contract. I want my money paid back to me and not credited on my account asap or else im taking this further on all social media and to the ombudsman.