Sounds like you have been screwed right through the transaction thanks to your agent.
Seems like he was working for the buyer rather than the seller. You say you sold it for much less than you wanted. Did the agent divulge your info to the buyer?
Print out the face book friend things and shove it to the agent quick smart and threaten to report him to the RE governing body.
Cheers
Yes I have been really unhappy with the agent and even though I have expressed my concerns to them all the way through they are really dismissive of everything I say. Can't wait for the whole thing to be over.