Blatantly refusing to communicate

I have sent them 30+ mails, they read them, but dont reply on them and close the case with no feedback.

I asked on phone asswell as on email to give me a cancelation letter with amount to cancel it, they just ignores it.

Reason for my cancelation is cos they are utterly ****mers, they phoned me last year to upgrade my plan, but they donwgraded it and when I query about it, they say they will escalated it, over a year now, still escalating.

Then 6 months back I phoned them, said Im using a trust, which dont allow debit orders, also send a mail saying the same, that I will pay eft.

Every month they blacklist my credit cause there debit fails, but Im paying monthly on eft and send them proof of payment, also the amount is R233, but I pay R400, so still they black list me on credit bureaus and on all my statesments it shows my eft payments

So I want to cancel for over a year now, but they refuse to communicate back to me, full of escalations only.