There is not a special Plat app, just the Amex one. I have 3 Amex cards, just received thr Starwood Biz card delived to my House on Thursday and created the login with no issue.

Personally, I would call back and try again with another rep for an expedited delivery. I do not believe that since it was Ameriprise Plat instead of the regualr one would cause these issues.

All my cards were delivered via UPS, fyi