I have seen other people post a similar issue, but there appears to be no way to fix this on my end and utilizing chat is the most frustrating thing because they don't understand the issue.
Problem:
Verification codes are being sent to the wrong phone number on the account.
Detail:
Attempting to link my AT&T account to a third-party app that monitors bills and creates a budget. Attempting to log in using my account requires a verification code being sent via text and entered into the log in screen. The problem is that the verification code is being sent to another line on my account. I am the primary account holder and the other line has no access to any account features. Going over every settings page shows my mobile number as the contact line for everything. I won't even get into how painful it is to navigate the AT&T website.
Desired Solution:
Make it so text verification codes are sent to my (primary account holder's) mobile number.