KFC STOLE MY R50 VOUCHER & THEY REFUSE TO PAY IT BACK!!!

On May 25 I tried to order on the KFC website a 2 piece and regular pap meal, the total was 39.90 and I entered the vouche that I was going to use (To the valueof 50.00). When I got to the checkout stage I realized that they won't deliver an order less than 70.00 so I removed the meal from my cart and did a new ordeer for collection. Only now it wouldn't go through it says I've used my voucher. When I look at previous orders it shows nothing. I have been trying to talk to them daily on twitter since May 26 to refund me my voucher. They last rep**** to my DM on June 23. KFC I want my voucher. I worked hard for it and it was not yours to just *****. I am tired of texting your page and getting no reply. Give my voucher back