Stilled getting billed!!!!

A few months ago someone from the Vodacom call center called me offering me a contract, so I told them yes I want it provided my old contract ends in November as it supposed too. The sales staff told me that yes it will end and no debits will go off! But guess what! It's December and I just got debited for something I didn't ask for! Now when I call customer care to refund me they keep giving me other numbers to call which I really have no time for! I just ordered a new cellphone for my sister which i am very likely to cancel if I do not get refunded! I do not want to have to deal with this in the future!