Cell C refusing to close my account

I have sent an email in January 2021 for a payment to be deducted from my account and for the account : Cancellation *** number. The debt order went through and the account was never cancelled till today. I have been treated unfairly as cellc wants to sponch of my money. I told them I no longer have that SIM card of that number. I’m really tired for their harassing call. The 1st email to close the above number was sent in October 2020 and they never closed it. I can’t be held accountable for someone not doing their job. Cell C doesn’t want to see themselves losing customers but they treat us like ****. I swear I will never ever take up a contract or advise anyone too.