EFT Payment Made

I had a Telkom data contract for 24 months. After the contract ended I reversed the monthly debit from my bank account. I then went to the Northgate branch where I opened the account to enquire. The lady explained to me that the contract continues unless the customer requests that it should be stopped. That was news to me as it was not explained when I signed the contract. After a few days I got a double debit from my bank account which I reversed because I expected the debit for one month. A few days later I then got an sms which explained that I should pay for 2 months after canceling the contract. The notification comes after the debit. No one calls to explain. Telkom agents call me selling products and I had a contract with them for 24 months but there was no communication regarding the contract. I never missed a single payment during the 2 years. I logged into the Telkom app to top up my data bundles then saw the bill for the 2 months. I paid it but have been receiving sms from Nudebt asking for payment for the same amount. I wanted to sign for another contract with Telkom by the end of the year but I think I will try another service provider. I called Nudebt and gave them the Payment Reference Number 2HYP180521. But I keep getting the sms