Been handed over to debt collectors for a bill

In 2010 I took a phone contract out with Virgin Mobile for my grandson who had just started work.<br> In 2011 he left South Africa and went to New Zealand permanently. Before he left I contacted <br> Virgin Mobile to cancel the contract. I was informed that the contract would be cancelled but that <br> I had to pay an amount of R697-00 in for the phone. I got all the banking details from them and <br> duly paid the amount into the bank. I then faxed the proof of payment. <br> <br> About a year later I received an sms from a debt collector requesting payment of the phone . I contacted them and was told that they cannot do anything about it. They need proof of payment. I explained that I had relocated and did not have the documentation any more. I contacted Virgin Mobile once again and explained my position to them. I was then told that the person who cancelled the contract had not right to do so, because you cannot cancel a contract until its maturity date.<br> <br> Things were left at that and I heard nothing more from them. Another six months went by and the debt collection department contacted me