The only way to access your hacked account is to first prove ownership by signing a message from any address/es you have used in this forum and following the instructions
as stated here. Send it to a mod or directly to theymos or Cyrus and then they'll check it. Be aware though that this might take weeks since only two people are handling this matter. Also, just a heads up, if your first message didn't verify, it is highly possible for them to not look at your PMs again.