Being Debited after the contact has ended

I just had a debit order go off my account . I took a contact phone with Virgin Mobile in December 2013 and as far as I know Cellphone contract are supposed to be for 24 months (2 years) which should have ended on 22 December 2015. I called in after seeing a debit order of R777.22 and the agreement was for R258.00 per month.I called in this morning and I was told that they don't cancel the contract without the client's consent. How is that even possible if the contract I have at home states that the contract is for 24 months and I had agreed to that? And then I'm told that I have to give a month's notice, notice for what!!? And then I'm told again that they have to wait for the proof from the bank , which shows that they did debit my account. Can I please have my money back and I want this contract cancelled.