POOR SERVICE

So there's a vodabucks where you receive coupons for different products and restaurants. What happened is that I had 90 vodabucks to redeem at nandos for 3 meals R49 each, due to those bucks I got myself a discount of R90. R30 off from each meal. I only had to pay R57 online. I went to Nandos kolonnade center to collect my meals only to find out that I still have pay R57 again since the 1st payment made through vodacom app does not reflect on their system. I called vodacom numerous times to check what happened to my online payment but I wasn't assisted. So now it means I have paid R114 for meals plus 90 vodabucks. I feel ****** and mislead by vodacom. I want my refund because the money went off my bank account.