cancellation of contract

Good day

My name its Mapule

I had a contract with MTN for 2 years, so now my contract ended in January 2020. In February i went to the same store (MTN Chilli Lane) where i took my phone to cancel the contract,but they said i need to phone the contact center. I called 135 several times, but was not able to get through to them. Then i decided to go to MTN in Greenstone to cancel the contract still they advised me to call 135 and they didn't even bother to assist in calling the call center while i was in their store and that time they keep on deducting money every month. I came back home very frustrated and trying to figure out how i will cancel the contract, i continued calling the call center for the past 3 weeks but still there was no help. Then today went back to the MTN store were i took my phone to check if they can assist in canceling the contract, i explained my situation to the gentle man at the store and then he called the call center line while was with him, but still there was no help. Believe me its so frustrating because every month they continue with their debit order of which i am no longer using their sim card and their service. And i will never ever use their service . All i need is to get someone who can contact me, so that i can be able to cancel the contract and will appreciate if i can get my refund back for the past 3 months, its not my fault that they are not answering their calls or delivering the service we need. I need that money back to buy my mom grocery. Your respond will be much appreciated.Thank you .