Vouchers dont work!

Good day,

I am extremely annoyed with your services and vouchers. First of all I have gone twice to two different Total garages to use my voucher and were not able to use my voucher as the system did not work. Therefore, I had to use cash to pay. Yes, these two times I have had cash on my to pay but what happens when someone relies on this voucher and does not have the money to pay. You are not able to see first if the voucher works and then filling your car which is pathetic. I have now had to pay R1000 for petrol when I have a voucher to use. I would like to be reimbursed this money and please can I have a voucher number that actually works.