What Frank said! Trot that contract down to your Attorney, first thing in the morning, to see if there are any gaping holes in it.
Now, that being said, I'm sure you realize, by now, that you should have done your homework BEFORE you autographed the dotted line.
Also, you need to consider whether your son-in-law knows something about it. In other words, did you really get screwed, or did you get an ok deal?
You mention a "3 day grace period", but you said the logger called a week after the contract. Your supposed 3 days would have lapsed, anyway.
It is obvious that you need to get some professionals involved, mainly a good lawyer, and a really good forester, assuming it's not too late for the latter.
Good luck!