Here's how to hijack the previous users' account.
In the phone, go to Options>Status and write down the pin. Also the IMEI number. Or remove the battery and the pin should be near the sim card.
Go to
http://www.att.blackberry.com/Try to set up a new account first to make sure the pin is even in use. You will enter the pin and the IMEI number. If you are able to create an account like this you are done and can skip down to the updating the os part. Most likely you will get an error saying 'pin already in use'. You will need the login info.
Click 'Forgot Password?'
Enter the pin and click 'request password'
Password is messaged to your device.
Call ATT or use the data support chat. Tell them you aren't receiving email for some reason. They will send you a test email
Using the scrollwheel find the test email sent and click. Choose 'forward'. Choosing this will let you see the email address of the recipient (you). It will be in the format of
dumbfuck@att.blackberry.netIn this case 'dumbfuck' would be the username and you have the password already.
Login to the account, change the email address and password. Note: the username will still be the old name even though the email has changed. Remember it!
Update the OS by downloading stuff here:
http://www.att.com/bbdownloadsFill out the forms with all fake info; nothing is checked.
Install the desktop first, then the device software. It will not work on wine
Then from your online account go to Settings>Service Books and click the 'Send service books' button.
Unfortunately ATT requires you to have a special blackberry plan or you will not be able to email, text or browse the internet even on a pay per use basis.