Vodacom Voucher assistance (or lack thereof)

I have recently upgraded my contracted on the website, part of the upgrade package was a R250 accessory spend voucher. I called vodacom today to find out how to redeem the voucher as I have now received the phone. I was put through from department to department and no one could help me and I was eventually cut off. This is unacceptable. All I need to know is how to redeem my voucher. How can no one know how to do it and why does online refer me to after sales who then refers me back to online. Doesn't anyone in Vodacom know how to do this?????? Extremely Irritated