Like has been said by others you're probabaly going to have to consult with an attorney to be made whole. Allstate and other insurance companies screw inocent people over to protect their bottom line. The sad thing is a lot of people will just take it, lick their wounds, and move on.

One more thing I would do is to file a complaint with your state insurance commisioners office (here's the URL for Texas http://www.tdi.state.tx.us/ and they have an online complaint form.) I don't know if they will do anything about your individual claim but if they're getting a lot of complaints about a particular company then I think they would do something.

Cheers
Bill