Cell C
3G never works

I have used a Cell C 5Gig a month prepaid speed stick for the last 2 years. It was great.
In December 2012, I purchased a 100 Gig anytime sim card. I can connect and send and receive emails every morning until 10am. As soon as it passes 10am I lose all connectivety. I cannot send or receive emails. I cannot access the internet. I have called Cell C 3 times and have logged ref # 1741974. They keep promising that someone will contact me. This never happens. I left a message for the team leader named Donavoan and he never bothered to return my calls.
My business is sufferring and I need help!!!