Mweb erroneously debiting my account after I closed it

I cancelled my subscription paid up my account end if 2021 and Mweb is still debiting my account. I reversed the debit because I closed my account with then because they didn't have coverage in the new area that I have moved to but now they sending me emails my account is in arrears. This is really pathetic very unprofessional and frustrating. They need to keep proper records of their customer accounts.