No communication on several emails

I have been sending email after email regarding standarbank mobile to be cancelled. I was informed of the process on 10 august 2021 which is 30 days notice. I have then requested to have the contract cancelled. Not one further email was received. I posted my cancellation query on their website and get told looking at the email correspondence I have never cancelled, and they can only cancel 1 May 2022 (8 Months after I have cancelled). I responded - highlighting where I cancelled and reminded them in all the emails I have sent