Facebook account hacked

My Facebook account was hacked with email and password changed. The hacker went ahead to change my username to his. All my effort to retrieve it back proved abortive, because they kept sending recovery link to the hackers email. I opened a new account with the same email to make a report through my friends. And also reported an imposter by sending my documents to them for identification.

I didn't get a reply, but later found out that my hacked account has been locked down as I type the name on it but couldn't find it.
New one equally disabled.

How do I retrieve my old account back?