i bought a new iphone 3g - unlocked & jailbroken. tested my sim of ATT and T-Mobile . No problem . configured wifi - no problem . i have go phone plan . i saw a option of buying data plan under go phone category . so i bought $20 of data plan - 100 MB for 1 month . i tested it and it didn't work . What could be reason of data plan not working on iphone . Is it not working as iam using iphone ? I don't want to buy expensive plan for voice and data . i want to keep go phone and data option so i can use it to call and if needed surf around also. please suggest . I can't call ATT support as this is an unlocked phone and as per them go phone plans are not supported on iphones.