Takealot has ripped me off!

I purchased a stock item in April. It was a DW DV Sound Card. The item arrived at my house faulty with lose pieces inside. I sent it back for a refund. I was refunded half of my money for the item. I was not happy, so I contacted Takealot and they refunded me with a coupon to make up for the bulk of the money. But here is the thing, they made the coupon to have a expiry date. I did not have the need to buy anything at this stage, so the coupon expired. I called them again and told them, please rather put the money back in my credit card. After a call back from them and me explaining that this is MY MONEY, the "coupons" department came back and declined my request to refund me due to it being part of a PROMOTION?!. How do you hold back a client's money and tell them it was part of a promotion? The coupon was the balance of money owed to me? I think this was an absolute ********* move from Takealot's part. If you are going to buy from them, make sure you get the right items and make sure that you keep every communication to them as they will rip you off in a heart beat.