iMac

Can anyone help? Me and my dad drove to an apple store today to try and get my iMac unlocked and have gotten absolutely nowhere! There is a 6 digit pin being requested that non of us know and apple claim they can’t remove. We have tried so many combinations that my mac is not locked for an hour and I could honestly burst into tears after spending a lot of money on this computer for me to take to university to now having nothing but a perfect computer that can go straight in the bin please please can someone help