Unfair system for clients

I had called two months ago enquiring when my contract was supposed to end. I was told on the 7th of October. I them said I would like it not to continue. But to my unfortunate circumstances I receive an invoice in my email. Being billed for November which I was not aware of. I have called about 10 minutes ago and they vodacom has informed me that they won't cancel until I pay the outstanding amount.I have said I will pay for the R210 that I am aware of but I cannot afford to pay for November as I am no longer working. Now how fair is it that I will be billed every month for something that I am not even using and I have stated my financial situation. I have agreed to pay for the R210 but what will happen from then on. I have been a Vodafone customer for more than 10 years now. And for the company to treat me this way is very disappointing.