I agree with the other advice you have been given about consulting a Real Estate Attorney on that one. If you don't know of any, a good place to look is at Title company's. With our Maryland contracts, you have an option to withdraw the offer, until it is signed by the other party. It is only an "offer" until all parties have signed. This is a very different situation with an auction and the "as is" clause, however, the contract may read "as is" at the time the offer/contract had been entered into. They may be responsible for getting the property back to it's same condition as it was the time you bid on it. It also becomes a material fact that the basement get's water in it.
All of these are reasons why you need an attorney on this, and you don't want to waste any time on getting legal advice on this either.
I hope this helps
The other agents are right. You do need to speak to an attorney. If you purchased the property "as is" I believe that would mean "as it was" when you first saw it and placed the offer. In most contracts, the seller is required to maintain the property and they clearly have not. Read over the contract and consult an attorney. Good luck!