I don't know the firm in question.
But did you use a lawyer?
Becuase after you had agreed the deal most agents step back and let the lawyers do the business.
Firstly you did not pay a reseravtion deposit?
Although I tend to advise clients never to hand over a deposit to an estate agent (I don't trust them!). I will however hand over a deposit to the vendor's lawyer after having done preliminary checks. A reputable estate agent will even allow lawyer to hold reservation deposit with proof of deposit/transfer etc.
I rarely pay a 10% deposit and prefer to move swifly to completion.
But any agent will tell you it's money on the table secures the property and the agent/vendor may have had doubts you would not proceed. It is a buyer's market at the moment but also there are properties that are priced to sell and do sell within days of being emailed around. So in that reagrd you have to move quickly do your searches and put your money down. I could give you an endless list of people who make offers and never actually buy - I sometimes think they are a strange type of tourist.
My approach does run the risk you lose the property but I have a 100% clean record of a client never having lost a cent. It's very hard to get money back from estate agents so don't give it to them in the first place.
So my advice to you is get yourself a lawyer and be ready to move quickly next time.
Let's see what our agent friends say!