maybe someone said this already but I didnt read all the replies - If they bought a property you showed them you may have a procuring cause situation
i.e. you showed them property A, then then went back a week later / submitted an offer with Agent 2 and bought property A.
Anything other than that you are out of luck, buyers agreements are complete waste of time and merely a show to make a buyer think they are signing something which on a subconscious level makes them think they are locked in.
It sucks, I had several people do this to me in my first year of real estate and there is no way I was not on the ball when it came to communication etc
Guy 1 was just a POS and kept telling me he was waiting for a new preapproval but would never give me the lender contact details - he strung me along for over 4 weeks (he had closed on a property and was still to chicken sh1t to tell me) I eventually found it on social media, called him out for being a pu55y and left it at that
Guy 2 went back a week later to a property we submitted a contract on (massively low balled and didnt get it, which was not my idea) with his friend who listed his home in the other part of town and who I had spoken to so to make sure he was ok with me being the buying agent and resubmitted an offer (the lender told me). That deal eventually fell apart and the friend dodged my calls until I called him from an office number.
Guy 3 - was a previous room mate, showed him several properties. Then I got injured and had to have surgery, had my business partner show him homes. Went under contract on home A - inspection came back with a lot of little things. He cancelled, a week later he told me he was moving out and had bought a home we showed him with another agent. I called the buying agent up and we got 25% referral fee. I kicked him out of the house after that.
the average real estate agent is a POS making zero money and will throw you under the bus for a dime, the average buyer is no different.
People Suck