No access to phone

If you had put it on auto pay you wouldn't have to worry about it.  🤷🏼‍♀️. 

Don't know what to tell you. You're right you don't have access to the account because you don't have phone. 

There are ways to refill a prepaid account without access to that account, though I’m not sure exactly how to do that. I seem to remember seeing reference to a website that only needs the phone number to refill. Perhaps one of the prepaid experts here will know.

There is the 'gift' option

https://www.att.com/support/article/wireless/KM1008660/