Shoddy service by MTN

I have had data contracts with MTN for a number of years, but I've had two more that I took out during the lockdown period. Two of the data contracts expired at the end of September 2022, but I was unaware of this until I received a vastly increased bill from MTN in October 2022. Upon enquiry, I was told that the data contracts were special discounts given to the public, but once the 24 month contract period was over, those special prices were no longer applicable, and the charges would be at the normal price, which was more than 3 times the amount charged on the contract. I wanted to cancel the contracts immediately, but was told that I must cancel promptly on the first day of the new month. This was done as instructed on the 1st October 2022. Due to various circumstances I did not check the account until the end of January 2023, only to discover that the contracts were still active. I went to the MTN shop in Bedfordview on Friday 10th February 2023 and related my problem. i requested that he put a cancellation notice on the system so that the contracts be cancelled immediately. He subsequently said that he left a message with MTN to contact me, which shoul take no longer than 3 days, and if they don't contact me by then, I should contact them. He also furnished me with a reference number. True to form MTN did not contact me, so I contacted them today. What a thorough disgusting experience!!! Firstly, the prompts were not clear, but when I did get through the first time after waiting a while, the call was breaking up badly. I asked the "client champion" to phone me back but I don't know if she heard me. I cancelled the call and phoned in a bit later. This time the wait was longer, but I did speak to the lady concerned. After trying to explain, she said that cancellations were not her department and said she would transfer the call. the phone went dead, but I saw that the time meter was running, so I heal on. Twelve minutes later, the call was answered and the ritual proceeded once more, and once more I was requested to hold on while she checked something. Once again the phone went dead and after waiting 14 minutes the call cancelled. This is not the first time this has happened with MTN and I am now heartily sick and tired of dealing with them.