Contract ****m,

I had a 24 months contract which ended and I have been a loyal client and never missed a single instalment,when the contract ended I kept on receiving calls to upgrade and I told them I was not looking to upgrade and requested a cancellation however I was told it’s not done through a call.I then went to Protea Glen Telkom store and requested a cancellation which I was told it would be cancelled the following month as it was already mid month.Few months later I was still debited and reversed the debit or and now Telkom is sending me massage that I owe them 1000.I feel ****med because I requested a cancellation,I am never taking contact with Telkom,they can sign you up for contract on a phone but when it comes to cancellation they make it difficult or impossible.When a contract ends why do you continue to debit a client?What does 24 months contract mean if after that I am still debited?