MTN South Africa Bad service

We had a data contract with MTN. The 24mnth contract expiry date was 26 November 2022. Because of constant bad signal in area, we have decided to not renew the contract when the time comes. On 25 October 2022, we contacted MTN to inform them of our decision and to give 30 days notice to cancel the contract when it expire. 9n 25 November 2022, we contacted them again to confirm the cancellation. Spoke to Senzo at retentions, he confirmed that the contract is cancelled. On 28 November 2022, we received the bill for the coming month, and that we are charged for the data contract for the month of December 2022! We called MTN retentions yet again, spoke to Cynthia Shabalala. She confirmed that there contract was in fact not cancelled by Senzo and that she will cancel the contract and will send a credit email to billing to rectify the mistake MTN made. It is now February 2023, and still no credit has been app**** to our current account. This is a frustating situation and MTN doesn't want to take any responsibility for a mistake on their side. I'm hopefull that Hellopeter will assist. I have all reference numbers from every call . Thank you, Douglas Shivas