I'm not happy with the service they are providing in terms of canceling the contract

I'm not happy with the service they are providing in terms of canceling the contract. My contract was suppose to end on the 31 of January 2024,however I was delayed to cancel the Contract. I've made a call on the 7th of February to cancel the contract however and I've already used the given monthly package (Data 2GB and 200 Minutes) which cost the amount of R580 and I was paying R604 on a monthly basis including the phone HAUWEI P20 They said that I will receive a confirmation sms for the cancelation till do date I haven't received the confirmation and when I check my app on Vocadom they is still available balance to pay month end, balance of approximately R580. Your assistance in this regards will be appreciated.