Get in touch Apple Store 5th avenue

ask your local Service Provider what they can do for you, or how to contact someone who can help.

Apple does not retain a copy of the receipt, so even if you or someone else were to go in person to that Apple Store, it will not help. They won't have it.

Keep your receipt after you buy an Apple device - Apple Support

Set a firmware password on your Mac - Apple Support

locked firmware is an anti-theft mechanism.

if the computer is yours, you should know the password.

if you do not have the password, you need to prove to the genius bar technicians that the computer was NEVER STOLEN -- this is harder than proving the computer is yours.

Typically, what they want to see is an invoice of your purchase from Apple, showing serial number. if there was a previous owner, they want to see a bill of sale from each time it was sold that includes the serial number, AND the original Bill of Sale. That is the policy.

On a given day, in a given store, you MAY be able to get by with less, or maybe not.

The process used COMPLETELY Erases the computer.

This machine was repaired in Apple Authorized assistance center in Portugal Company name is “Tou aqui tou aí” (many years ago) under my name (easy to prove)…screen and keyboard replaced…for sure Apple has this repair records….its on my name and my Apple ID…I can get the invoice of this repair….

I think your best chance for success by far is to return to that same store and ask them to help.

Can you tell me how can I get in touch to the Genius Bar technicians…

As much as any of us on this site would like to help, we have no way to do that. Even if we did, the Genius Bar technicians would require you to appear in person with the documentation they require to definitively satisfy them the Mac is really yours.

Apple can help — if — you prove it's really yours.

As much as we might like to, none of us on this site are in position to assist you though.