Bad vouchers , horrible

I am highly disappointed in vodacom. This is the econd time a food voucher I got on your app shows invalid. The first one being a spur voucher and now steers. Yall deducted money for the spur and I didn't use it and now the same thing is happening with a voucher I got 5 mins ago!. I need to know how to rectify this ASAP as this is unacceptable , why sell vouchers if it is never valid