Got my US acc hacked a few days ago too as I did not managed to sign in to psn saying my sign in email is not valid. Checked on the email and received the sign in change email meaning someone did make a change to the acc the previous day. I was thinking of calling the us support from the office the next day when a friend is kind enough to lend his vpn acc for me to chat with the us support. Managed to recover the account within 5 mins. All they ask me is the original sign in acc n username. Make sure u have access to your e-mail registered as the sign in id as they will send a link for you to reset the password.
Oh btw, they did asked for a us contact number I just replied I don't have any. Maybe they want the contact for the 2 tier verification.

Anyway, good luck.