Refund for services Cancelled by CemAir

In December 2018 my flight (Flight Details: 15th Dec 2018 with reference number AAP9XO) with CemAir was cancelled by CemAir. I was forced to make alternative arrangements and incur unplanned costs due to the short notice in which the flight was cancelled. As per email correspondence with CemAir, they have assured me that I will be refunded fully. As per further correspondence with them, my refund would have been processed on the 07th of March 2019. To date, I have yet to receive the refund, it has been four and a half months since my flight was cancelled. When I made the payment it was instantly deducted from my account to theirs it did not take four months. I now have to carry the cost on a credit card that charges me interest while I wait for CemAir to repay me the amount without interest. I urgently request that my refund be processed.