Forced to pay to money I can't afford

I am not happy with the vodacom. I called in this morning to cancel the data that I'm getting because I can't afford anymore the lady by the name Apricocia she they can't cancel because my account in arrears which means come the 1st I will be allocated the same data I can't afford I am forced by vodacom to pay something I can't afford in these trying times where by I'm looking to settle the account the will always be behind and il be handed over because of the R420 extra that I no longer have. I've been with vodacom for 9 years but this is by far the worst I have received.