Telkom very wrong

I signed for a SIM card that offers data and all was done I submitted all docs that were required from me.The problem came when they deducted the debit order from the bank that I did not authorise the bank that I did not ask them to deduct from and I don’t even know where did they get those banking details from as I did not provide those details for that bank, I feel that they invaded my privacy and now because they debited from the unauthorised account they did not find the money because I did not provide those details and now they are charging me for the rejection fee of R200 and mind you it’s not even my fault.My biggest concern is, I need to know how did they get hold of my banking details that I did not provide them with.I need a full explanation and I need to be refunded my R200.I need justice to prevail in this matter.