Mr price mobile

I was give a SIM card in store 2016 November and told its a prepaid sim which was ricared in store. I have never used the sim to date and recently discovered that the SIM card is contract and mr price mobile have deducted R125 every month since 2017 January . I'm being billed for a sim and I never agreed to the billing. The store manage cannot asssist me and was told by a consulted over the phone that they is no audio recording of me agreeing to the bill and there is also no paper work at the store to confirm that I agreed to being billed monthly