Wrong email on my account and cant get confirmation email to setup my AT&T account.

How do I get my account email changed if it's not technically created? It's a new line and I preorder the Samsung S21 Ultra and the employee didn't put the #4 on my email address so I'm not getting updates on shipping for my $1,250 phone and cant create a MyAT&T user account because it keeps sending the confirmation 8 digit code to the wrong email address.  Please help as my phone is due in 2-3 days!