Shake everyday with Vodacom is a ****

I've played shake everyday with Vodacom. I received an SMS with a voucher from them to say that if I spend over a certain amount at CNA I should give them the ref code and will receive a discount. I purchased a few items from CNA and when it was time to pay the code didn't work. It's not the first time that this has happened according to the staff at CNA. This shake or play everyday is a ****. They send you sms's to say u have an entry into the grand prize draw that the date changes every time and no one is named a winner! Worst network! Will definitely be porting over