8700c gophone service

8700c gophone service
I'm planing on going with att gophone other than pay as you go messages what hacks do I need to do to make it work.

i use an 8700c with gophone, you cant use push email, but you can make/take phone calls, txt msg, with regular plan, for inet useage, you have to buy a data plan which costs,
1MB 5$US
5MB 10$US
100MB 20$US

other then that works fine, at&t even unlocked my 8700c i bought from ebay... (but ihave been a gophone cust for over a year now too)

pixelated display

I also have 8700c been gophone user for two yrs with data plan worked fine with old nokia phone. My 8700c unlocked phone works fine with voice & text but get nothing with data. AT@T says I have to change over to a contract with them for my data to work. Does not sound right. Did I make a mistake by activating my 8700 with AT&T? My old nokia still works with sim card and I get data on it. Help please