unauthorised debit

on the 14/07/2015 I visited Capitec Bank and was advised that the company had effected debit orders of R79.99 on my account. It was the first time I heard of this company who upon being called indicated that the debit was in respect of a cellphone contract and could have been effected in error.I do not have a cellphone contract and am wondering how my bank details were accessed.this must be an inside job and a big **** is going on.on calling the company I was attended to by one EMILY who was rude, promised to investigate and call back before banging the phone down. I require my refund and prosecution of these *********.