Problems with account

Before this accident I had iPad Pro 12.9 (iOS 10 beta 3), iPhone SE(iOS 10 beta 3) and MacBook Air (late 2014, OS X El Capitan).

When I returned home, I found that my Apple ID is blocked. I reset my password at iforgot site(password was generated in keychain access). Then, I saved my password in keychain access as new password. I tried to log into account using new password, but password was incorrect. I was sick those days, so I stopped trying to access my account.

2 days later, I tried to sign in my Apple ID account, but I couldn't do this. I lost the recovery key, I had no trusted devices, where I've signed in with my Apple ID and I forgot my password. So I registered a new account (like it's written on apple.com site). I signed in new account from MacBook Air. Then I tried to sign out of my old account on iPad Pro but it asked me to turn off Find My iPhone function using my old account password. Same with iPhone SE.

Then I thought that when I'll recover my devices, I'll just start using them with new Apple ID. Now I've recovered them(now they're running iOS 9.3.4), but it asks for my old account password, because I haven't deleted them from my old account and I haven't disabled Find My iPhone thing.

Please, help me.