WTF People? #4: How the fuck did this happen?

We are trying to sell a house right now and were scheduled to close on it this week. however the buyer is financing through some company like what you see on tv and is having a lot of problems with them. That's not what is pissing me off.

We were informed by the title company that we don't own the land we thought we had owned for 15 years. Apparently somebody acquired not only our property, but half the block we lived on as well and never informed the residents. I thought people couldn't legally do that. Well, now we have to sign an affidavit saying that we never knew of such a transaction, but the guy's attorney has advised him not to sign any so called "quick claims". So now the closing has been suspended until this whole situation is cleared up.

I want to know how a piece of land we had finally paid for in full five years ago can be sold/ acquired to/by a private individual without the consent or knowledge of the original owners. Furthermore, I would like to know how a person could take possession of half a block of a residential neighborhood without the owners' consent or knowledge. Is that even legal?

On top of all that I have come down sick. This is just a really bad day I think.