You are about to start a long journey to get your account back (accounts recovery is not a priority for admins) but first:
Prove the ownership of the account which can be only by signing a message from a btc address you posted before (not the one set in your profile), in your case it's the same used in many bounties you joined [I
archived one of those post for future reference].
In some cases, users involved in account-selling(
discouraged) asked to recover accounts after selling it and it seems a little bit strange that your account hasn't been active since August 16, 2018 and the password has been changed three times after the date of the last post [
archived] which was in July 23, 2018 (today you discovered that your account has been compromised!!!!) ; so if you can sign the btc message, just post it here and ask a moderator to lock the account or tag it until ownership verification. {I think moderators may accept the proof of an eth signed message [
archived] to confirm that you are the real owner in case you can't sign a btc message but in this case you will just succeed to lock it to not be used by the hacker but you will have to forget about it forever}
I don't know how your email may be hacked but my last advice for you is to set a secured email for the recovery and not the one you used to create this account because two accounts can't have the same email address.
Useful links:
Recovering hacked accounts or accounts with lost passwordsHow to sign a message?!
