Internet on my android phone is not working?

[Megan]

I got a new phone (android) on contract last week which includes internet allowance. I'm still using the same sim card. My internet was locked before on my old contract because I kept going on Facebook and it kept charging me so my dad locked it so I couldn't use it, but the other day he unlocked it so I could use it again because now I get internet free. But it won't work, I can't log in to Facebook or Twitter and when i go on Market it says 'A network error has occurred. Retry or cancel'. Msn messenger works sometimes though. I downloaded the apps through wifi by the way. I'm so confused and just want to use internet please help!