If the hacker set emails and recoveries on the account you will have a problem, there is no real way to "lock" your account. Your only hope is to go through the recovery process and give as much info as possible while also adding a note that states the hacker added recovs and an email.
You won't be able to lock your account if you don't have ownership of it anymore lol, also i think they did away with locking accounts, have a look around on account management on RuneScape