Frustrated!!!!

I have an African Bank my world account and if you swipe your card ten times in a month, you qualify to get a R150 voucher. So, I got a voucher and I chose to get a checkers/ ShopRite voucher. There are a few different vouchers you can choose. Any way, I go to checkers today, buy what I needed and when I get to the till. I can't redeem my voucher. It says campaign is over. So I phoned African bank call centre. After many calls. I eventually got through to them, to be told, we can't help you, phone on Monday that division is off until then!!!! What help is a help line if no one can help you!!!! I am so upset as I'd banked on the voucher