Upgrade and paying for two phones

HI. Round about the 25th of January I done an upgrade at the Canal Walk Cape Town CellC store. I requested that the upgrade only kicks in after my (then) existing contract ends which is the end of May 2015. while at the store I received sms's that my upgrade is successful. I also received sms's that the data and minutes was loaded. I then asked the consultant why am I receiving these sms's. she did not know and called her supervisor (Tyrone). He did not understand what happened because according to him I was not on a contract, I was on a month2month. I told him that I am not and that my contract is to end at the end of May 2015. he said he will escalate it and get back to me. he did not get back to me. I now discover that I have to pay the remaining 4 months on my old package and my current package. I discovered this when I received my statement. I made several calls to CellC, of which they say I have to go back to the branch and request a reversal of the upgrade. I called the branch. The consultant is telling me they work different to CellC because they a Franchise. She also agreed she did not know I will pay for both packages. I am not prepared to pay for two packages.