Cannot activate Apple Watch NumberSync because of dash in my e-mail address
So, I just got my brand new Apple Watch series 5 and I want to enable cellular NumberSync. I tapped through all the sign-in and setup-up screens until I get to the confirmation screen to add my device to my plan. It's required that I enter my e-mail address so AT&T can send me updates about my order, but I keep getting a form error telling me to "Enter an email address" and I can't continue. The user name part of my e-mail address happens to have a dash ("-") in it, and if I remove the dash the form error goes away--but then that's not my e-mail address!
Are there any workarounds to this glitch, or do I have to wait for AT&T to (hopefully) fix the bug in their sign-up forms? Don't tell me to get a different e-mail address--this is clearly a bug in the sign-up forms.