This happened to me also. I had to contact support. Here's how: on the app, tap the right facing arrow on the bottom left/middle screen, the click Settings. Scroll down and you will see the button for Support. Click the yellow button in the upper right that says "My Tickets". From there you can open a new ticket. Explain to them what happened and ask if they can reset your password. Your User ID is your game name. As part of the reset, they will send you a confirmation link via email. Be sure you confirm your account by clicking the link in the email. If you don't and anything goes wrong with your app or your account, you could lose everything (Support told me this because I had to reinstall the app, which apparently is not uncommon because of all the updates to the game. Sometimes the updates make the app behave strangely and a reinstall is necessary (not often, thankfully)). Hope this helps!
So while trying to get this to work, I created a second acct. which is also linked to Facebook. I went to look at the Facebook app settings and FoE shows up twice. The working acct. has an email address associated with it in Facebook, and the non-working acct. (the one I use), does not! And I don't see any way to associate an email address with it.Hmm...I'm not sure what you should do. When I had this issue, I ended up deleting my first city (I hadn't done much or bought diamonds) and starting over but I also didn't contact support. I'm sure they can help you. It may take them a few hours or a day to get back to you.Well, the plot thickens.