Why can't I connect to the app store when im on wifi?

I just got a white iPhone 4s 32gb from AT&T two days ago. I was downloading all these cool apps and everything was working great. One minute I was connecting to the app store over wifi the next minute it wot let me. If I have wifi off I can connect to the app store but as soon asi connect to the wifi the app store no longer will load. I have hard reset my Phone, tried multiple routers, reset network information and done everything short of taking it apart. My ip is not 169. Or anythIng of the sort. When on wifi I can connect to safari and surf the web. I don't understand why this is happen and have searched all over and nothing has helped. So I have come here to ask for help as it is very frustrating not being able to download larger apps because I can't connect to the app store over wifi. Thank you.