Speak with an attorney and/or the agent's Broker Manager, especially if you have this conversation via e-mail. Verbal agreements may not have any recourse, however, the e-mail might.
Even though you made an intention to purchase a house, verbal or in writing, it is not sold until:
1. The owner of the house signs off on the purchase contract and purchase price.
2. Escrow is opened, funds are transferred and new title is recorded.
Also, agents can not take listings off of the market without the owners written request.
Everything needs to be in writing to be enforceable.
That's unfortunate..I can only imagine how frustrated and upset you must be.
I would be to.
Susan Bo'ur Realtor Coldwell Banker