Ongoing frustration with payments

I am extremely itate with Cellc which seems to be ongoing from month to month. Since July last year I have requested for my debit order to bve changed as my payment dates have changed. After much deliberation and frustration I was denied. I started making payments by depositing it into their account and sending through proof of payment. Despite this paymentmy account is still debited every month despite the numerous calls. I keep sending through proof of payment but cellc still double debits me. I never get refunded my money. Cellc is so incompotent!!!!! I want my money to be returned and my contract cancelled immediately.