MTN service a disgrace

Struggling to cancel contract I went to MTN K90 Centre in Boksburg to cancel contract on cell nr ********** on 15 December 2020. The lady submitted the request and said that the Retention Dept would phone me to confirm cancelation within 3 working days. No one contacted me and the increased amount was deducted from my account. I went back to mtn on 4th January 2021 to enquire and they gave m a number to phone. I phoned a few times and had to hold 20 to 30 min a time before they answered only to transfer me to retention dept where I jold on for 30 min. No one answered. This is disappointing service. Please cancel contract with immediate effect