UPGRADE DONE WITH OUT MY CONSENT

I have never been dissapointed like this in my life .I have had my vodacom contract for over a year now .I called vodacom's upgrade department asking about their data packages which i was thinking of upgrading with .The agent explained everything to me of which to be honesty i was not interrested in because it didnt make business sense .Before we could end our conversation she asked for my email address advising that she wants to send documents .I then told her that i dont want to upgrade now because i am not sure if I want to upgrade with a phone or data .I even advised her to call me the following day so that i can tell her i want .Guess what she went ahead with the upgrade ,I checked my balance on the 1st of November and i had 10GB of data .I called vodacom and they confirmed that there was an upgrade done on my phone I TOLD THEM TO REVERSE FRIDAY ALREADY .It is now Thursday and I havent anything from them . when i check my bill it is double the amount that i was paying before .where on earth will i get the money ??