Furious Customer

I've purchased vouchers on the Vodabucks store on the 21 August for Nando's. I first bought 1 for R200 and when I've chosen the items, I've realised it's too much so I'll need to go and buy another voucher. I then cancelled my order and went back to the Vodabucks store to buy a R100 voucher. Went back to yhe Nando's app and when I wanted to used both vouchers at the same time, the app said I can't redeem because I've already redeemed it. I never redeemed it. So I've called to the call centre the person I spoke to didn't even had an idea what I've been talking about (the voucher) please educate your staff. I think it took me 3 calls to finally find someone to log the problem, but I still doubt her because not number was given to me of the call logged. She told me to wait 3 business days for a response. I've called again on Friday to confirm if she didn't eventually log the call for the refund off BOTH vouchers, because I had to buy from another restaurant. To date, no refund had been received!!!! Can this please be looked at and provide me with feedback.