Worst service provider

Worst company I have ever taken a cellphone contract with. Took one about four years ago, paid less than R400 for 24 months just as agreed then I canceled my contract with them surprisingly they still debit every mnth from my account but now they debit R1200 plus. Every other week they try to debit, my account is on a minus because of them. I am at home not working because of covid19 and they are just making things worse for me. Cannot even get assistance from their call Centre. *angry*