Not paying me my double paid premium back!

I paid my monthly premium into Momentum's account and then on the same day they debited me. Easy mistake. I immediately phoned them and they said I must send an email. I sent an email. I received an automated response with a case number. That was on the 2nd of February. Today is the 13th of February. In between this time I have phoned around 3-4 times to find out the status of my refund. Today I phone only to be told they have listed it as a credit and not a refund!! This after I was told just a few days ago that they were marking my refund as urgent as I have not paid my rent in full as a result and am now being blacklisted by my property agent!!!!! This is absolutely insanity!!! If I hadn't paid, I can guarantee you I would be getting a million phone calls and no benefits! Pay me my money back!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Immediately!!!!!!!!!!!!!!!!!!!!!!!1