NFLSUNDAYTICKET.TV Login Issues

I just purchased the NFLSUNDAYTICKET.TV To Go plan, but I'm unable to login with the NFLST app. I can login to nflsundayticket.tv ok, but not with the app on any device (iPhone, AppleTV, etc.) All I'm getting is a message that says:

Looks like you're using the wrong login credentials. Remember, the NFLST app uses the user ID and password for your DIRECTV or the NFLST.TV.

I've called Tech Support twice and was on the phone for nearly 2 hours and they were not any help. All they said is that there's a known issue with the apps and DirecTV is trying to fix this? I'm not really buying that and I think there's a bug in my account setup, due to having other AT&T services using the same email address.

Here's what I've tried so far:

• Deleted NFLST app and reinstalled.
• Confirmed I have the latest version of the app on my AppleTV.
• Rebooted devices multiple times.
• Changed e-mail address on nflsundayticket.tv to a different email than my ATT Internet account
  • Once I did this, I now get an error message that says "We couldn't find this email address and password combination on file. Please try entering your info again." I'm able to log in fine through my internet browser without receiving this error.

What do I do @DIRECTVhelp? I think I've got a legitimate account conflict somehow and it's not just going to magically fix itself come Sunday, especially with other people able to see scheduled games correctly (according to this other thread).