These are user-to-user forums, you are not talking to Apple here.
What iPad model is it ? It's not available on the iPad 2, and it will only appear on the iPad 3, 4 and Mini if your carrier supports it - you may need to check with them to see if they do support it, and if you are on the correct tariff with them.
Do you mean that the iTunes app on your iPad can't connect to the store, or that the iPad doesn't show when connected to your computer's iTunes ? For the first have you tried logging out and back into your account. For the second :