Responsible for Closing Costs?

I am a real estate investor trying to close on my first house. It seems that the seller will not sign the deed.Am I responsible for closing closts, as title work has been completed? Also, as the house is near foreclosure, how long am I legally bound to the Purchase Agreement?
Would appreciate any and all feedback…Thanks

These questions are answered in the purchase agreement itself - or at least should have been!

John Hyre