Zero stars for appalling Cell C service

If I could give Cell C zero stars I would. I have been a loyal customer for some 15 years to Cell C, in December of last year my phone was ******. I immediately called and blocked the phone and number and asked to cancel the contract which was finished and paid up. I spent over an hour on the phone from overseas doing the cancellation. Since then even though I was assured it was cancelled I have been billed each month for a contract I no longer have. I have tried several times from overseas to try and rectify this with customer care every single time they transfer me from one department to the next and eventually just hang up the phone on me. I have tried calling at great expense to me as I am in America, I have tried emailing to which their reply couldn’t even get my name right and to no avail. I am at my wits end and then they have the absolute nerve to hand the account over an account that I haven’t been able to use for 3 months as the number and service is blocked! The service is beyond shocking and would not be tolerated in any other country. I am absolutely appalled.