Thanks...just phoned that number and finally got to someone who seemed to know a bit more. She said the password reset links are never going to work once the account is locked from 3 incorrect attempts to enter a password. The only way to unlock is to email a copy of my passport and a bunch of other information to an account reset group, and she showed me the place on Delta.com to do that. (It's pretty well buried...I never would have found it myself.)

Crazy frustrating process, but I guess it's my fault for forgetting the password to begin with. Clearly I don't fly Delta enough...this is the one password that I don't know offhand and the one I had stored in my password tool is apparently out of date.