Verizon iphone service problems

I have had an iphone 4 for about a year and a half about 2 months ago i had to get a replacement because the buttons werent working. But lately for about the last 2weeks my internet service hasn't been working without Wi-Fi. I have Wi-Fi at home so it works fine but the minute i leave my house it say i have no internet service when i know i do.could there be any reason it wouldn't be working like a setting or something? Plus i'm paying for the internet service!

You shouldnt change the setting from your house internet to the verizon internet. It just seems like when people do that sometimes it doesn't change the setting back