You had a contract to buy the condo and, during the time the contract was pending (prior to closing), the condo was destroyed, condemned, or something similar?

If so, you should seek legal counsel (or at least discuss the situation with your real estate agent/broker). Virtually all contracts to purchase real estate have a clause or clauses that address this scenario.

Agreed ... since the seller cannot give you clear title there should be a clause that not only lets you out of the contract but also gets your earnest money back.  Seek a real estate attorney if necessary.