Cancellation of Subscription and Refund

I requested CellC Get-It for cancellation of subscription since June 2015 but it was not effected. Following failed attempts to request telephonically, I wrote an email in September 2015 for cancellation with immediate effect. Again there was no reaction. I called again in December 2015, a consultant promised to escalated to the supervisor. Despite many attempts, the debit order is still running against my account. I demand immediate cancellation and full refund since June 2015. Thanks.