HELP .. Offer accepted... what's next?

Got my offer accepted from lender but all they faxed me was a demand letter saying the amount they wanted to net and a dated they wanted to close by, 10 days from now, which is impossible for me. I’m not to worried about the close date but about the lack of closing info.
My lender tells me he needs a contract signed off by the lender for the reduced payoff amount. What are others experiences on this phase of the process? I will be calling them in the A.M. but just wanted a heads up.