Activated gophone but can't get into account

I had a gophone, but time passed and forgot to renew card, so had to get a new number.
I activated phone per instructions, received number, waited the time needed, turned phone back on and tried to buy a $100 card, but the ATT site says number not recognized.
The phone does not show the phone number, the space is blank.
The booklet says the password is the last 4 digits of the number, and thought that may have been wrong, so tried to have new password sent, but still shows number isn't valid.

I thought the activation may have had a glitch, and thought about trying to reactivate online instead of on the phone, but decided that may screw things up even more.

I tried creating an account, like my old one, but still number will not work for it.

Ideas???