Well, Thank you, and I understand the frustration. While doing this I tried again to get my 2nd account working and I still can't change the password.
If you do what I suggest, you should have it done in like 5 minutes though (As long as you know your current password). As far as how long will it be before they change it again? IDK. that's not anything we can control. It's inconvenient and a pain in the ass, but it is what it is. You can get back on if you really want to, you do need to take a few minutes to do so though.
Modern gaming, with internet, accounts, $$ involved, etc just don't mesh with the "plug in and play" way we used to play games. There are a fair amount of retro gamers here for a reason!