Bad customer service!!!!

Blue Label Connect Telecoms offered me a cellphone contract which I accepted. the following day after giving it a thought, I cancelled the contract as I realized that I will be paying 2x more than the normal price. They still delivered the phone even after cancelling the contract. I was told that a debit order will not go through because the phone was returned. On the 29th of April they still debited my account and now when I call them, they are giving stories about providing a bank statement even though I gave them the debit reference they could not refund me. I am unable to do a reversal at the bank as they it is blocked.

I am so disappointed and angry as I am being debited for a device that I do not have. Blue label connect can I please have my money back