Data contract

I had a data contract with Telkom which ended last year 2015 November,I was told that if I want to cancel the contract iI must give them 30 days notice.On the 14th of January 2016 I went to Telkom mobile shop in centurion mall and I filled in a cancellation form to cancel the data contract .I was assured it will be cancelled in 30 days.On the 26th of February I went back to the Telkom mobile shop to ask why is my contract not cancelled and I was told to phone Telkom 081180.On the 3rd of March I phoned the call center and asked why is my contract not cancelled ,they tell me they can't pick up my cancellation form on their system.They tell me I must go back to the Telkom mobile shop and I told them that I am not going to run around going back and forth ,it's not my fault somebody didn't do their job and I am not going to pay for contract anymore .I don't want this contract anymore ,I did my part went to Telkom and cancelled it and their employees didn't do their part. Now their billed me and debited my account .I want my money back and this contract must be cancelled with immediate effect.The Tellom shop told me I must wait another 30 days ,who is going to pay for the next 30 days.