Recovery for 2015 MacBook with Big Suru OS

I forgot my MacBook password.

MacBook suggested a recovery using Apple ID.

Lock-pad image for Apple ID password entry appeared.

(It seems MacBook at firmware mode, I guess.)

I entered Apple ID password but nothing happened.

I went to Apple Central World in Bangkok, but it seemed they don't know what to do.

(Recommending me to buy a hardware replacement at 500USD.)

Any suggestion?