My contract was not cancelled/deactivated

I went to Mokopane MTN store SABC2439 and I wanted to cancel one of my contract. I was assisted by sales person names Awelani Radamba and I made a payment of R580. He gave me a paper as proof of deactivating my contract. I was happy it was done then come billing date I m billed as normal but not the final, only to find out it was not but I have a proof to show I wanted deactivated. No one took accountability in that store of the inconvenience they have cost to me. I currently have 4 expensive contracts with MTN and I was treated so poorly and no accountability taken. Now I have to pay more to cancel with what money because i went to the store cancel but it was never done