Samsung Galaxy S Advance — Can't get data to work over cellular network (Help)

Just switched from HTC to a pair of Samsung's newish Rugby Smarts with Consumer Cellular served by the at&t network. When I shut off my Wifi or I'm not connected to a Wifi network my data will NOT move. All my network apps state the same "Network is down". As soon as I connect to a Wifi, it all works well again. So, obviously, the network is NOT allowing data.

I've spoken to CC's tech support and they confirmed that my plan has 2GB of data/month and its activated but yet, no data goes/comes.

Can someone please provide a solution? This is getting old as I'm on the go a lot and depend on emails and web searches.

Thanks