Did an upgrade still paying for old contract

I have taken a 24 months contract in Sept 13 and expires in Sept15.<br> My phone got ****** in October 2014 last year and I went to do an upgrade and sim swop at Umgeni Road Cell c store on the 29th November 2014.<br> No one at the store informed me that I will still paying for my old contract and that I cannot do an upgrade, only told me that I have a month to month contract.<br> When I received my bill for Dec14 to Feb 15 I saw that it was very high and I then queried it with the cell c billing department and they informed me that I was still being charged for my old contract.<br> <br> This is not acceptable because why didnt any of the consultants from the store tell me that I cannot do an upgrade cause I have a 24 month contract on my old phone and why am I still paying for a phone that I no longer have with me.<br> <br> Cell c must credit my account for the overcharges from Dec 14 to Feb15.<br> <br> Utterly dissappointed.