paying for a number that is not mine

I'm being billed on a cell number that 'does not belong to me'. I even get statements for this number. I tried to get this number removed from my name, but nothing can be done unless i call the cancellation number, which i have now done twice. It says i will receive an sms or email to confirm the cancellation, but i have as yet not received either notification. I've been in to the store a few times and was told i can only cancel the number by phone. When i go to my vodacom profile, the number cannot be cancelled as it 'does not belong to me'. I am paying for this number every month. I get calls to upgrade this number on a regular basis and when i say the number is not mine, i just get told ok, good bye. This is money that i do not have to pay, but it comes off my account every month. Question is: will i get my money back for this 'number that is not mine' and have it removed from my profile in time for my next bill payment.