Cancellation of debit

I am not happy with this company at all, I have signed up with them and they were very much available on calls and app whenever I needed them , now I happened to be lucky to receive enough cash to pay all my debts and now I want to cancel my debit with them , they are not responding to my WhatsApps or calls an they told me that I can cancel at anytime, they now have changed saying they can only give me payment break and I told them briefly that I need cancellation, they are no longer responding to my call or WhatsApp yet they want to continue debiting me