Mtn debited from my bank account.

on the 24th December 2015 I registered for Eazy Recharge as I wanted to buy data bundles but it was not successful. on the 29 of December 2015 without any request to but Airtime or Data bundles Mtn just debited from my Nedbank account, First debit orders was of R120 , second debit order R200 and third Debit order R100 on the same day. I called MTN and spoke with Few people, most they told me they don't see any transaction that took place it was like I am crazy or I don't know what I am talking about. one lady said she will send request to Eazy Recharge department to call me. and I did receive call back from Faith on the same day 29/12/2015 and she said she does not know what happened with the system because the request for airtime failed and I explained to her that I never requested any airtime on that day and total of R420 was debited from my bank account and I want it back. she said I must wait for 48 hours to see it will be reversed or not and it was not reversed. on the 5/01/2016 I called MTN for refund and they said they don't see any money that they debited from my bank account. I ask to send by bank statement for them to see and they refused saying they will come back to me