How to get 3G on my iphone 4?

I have about the web pack with Vodafone and I waited for the text I got the text and it said it was activated but I have the icon (3G) at the top but could not go on the internet what do I have to do thanks courtney x

Call GE, THEY KNOW THEIR ONIONS!

You could contact Vodafone (should be vodaphone in my opinion) but i don't know i live in the US