Annoyed with poor service

I have phoned to cancel my data contract which came to this year July. I phoned as per the recommendation, one month prior to the contract expiring to cancel the contract. I did not keep the record of date and time as I was confident it would be logged. On 21 August I received a phone call asking if I would like to upgrade this contract. I was surprised as I thought I had cancelled it. I phoned again to cancel this contract on the 21 August 2020, at 12:04 and spoke to Sinesha. She then indicated that she had cancelled the contract and that I should receive an sms in 24hrs. I still have not received this message. I see that my latest deductions that the amount is still being deducted for this contract. I WANT TO CANCEL THIS CONTRACT WITH IMMEDIATE EFFECT!!!