Refund delay tactics

I recently bought two simcards instead of one. I called the call centre immediately to be cancelled before it can be debited ( Order Number ***). Unfortunately, it was not cancelled and I was debited twice. I called on numerous occasions and was told that the ticket was logged to billing for the refund. I am still waiting and failing to understand what is the hold up with returning the money that was debited. Yesterday, both simcards were delivered I still called regarding the refund but still nothing concrete.