Customer Service
Dial *611 from your cell phone
(800) 922-0204
Monday-Sunday 6am-11pm
As far as verifying, I'm assuming that since you are a teenager that your parents are the account holders. Given that, you are going to have been given access to the account by the account holder in order to make any changes. If not, you're gonna have to have your parents to do the password changing for you. (I know this because this happened to me: I created our cell accounts, used MY card to pay for the phones, but put everything into my husband's name. When it came time to make any changes, I had to have him speak to the rep and give me permission to do the account thing. And we had to set a password.)
So unless you've been given permission by your parents TO the company (they'd have your name on file) then you'll have to have them do the changes.
If the account is in YOUR name, then you're only gonna need your cell #, your password to access the account (if you set one), and your name and address on the account. As far as I can remember, that's all you need. You might need more, including ssn. Good luck!
deb