Apple ID is not active and i can't log in

I have 2 Apple IDs on my iphone and suddenly one of them stopped being active. I tried to google the problem and nothing helped me. Cuz i forgot the password to it. And i cant change the password either cuz the Apple ID is not active, so it happens to be a never ending circle. I really need to get the access back cuz in other case i'll lose a lot of important data. What do i do?