ESTATE AGENTS WHO ARE JUST CHASING COMMISSION

MY HOUSE IS WORTH 900 000 BUT THIS ESTATE AGENT NABOTH GOT HIS FRIEND FROM ANOTHER AGENT FOUND A BUYER AT 810 000..UNDER DURESS I ACCEPTED THE OFFER..FOR 2 WEEKS I HAD NO CONTACT FROM THEM OR THEIR ATTORNEYS I DID NOT KNOW IF THE DEAL WAS ON OR OFF...I THEN SECURED A BETTER OFFER...BUT WHEN I WANT TO DISSOLVE THEIR OFFER... THEY ARE THREATENING MITIGATION