Ups lost my guitar! I need some help with some question please help!!!?

I had a guitar shipped from Dallas to Houston, with ups, it had overnight shipping so it would not sit in a warehouse, it was supposed to be delivered on tues 4/5/2011, but I never got it, ups tracking number online says it was left at front door, bu it was not, i waited at the door all day, never saw a ups truck go by. the shipper started a trace process, I'm just wondering what is gonna happen, where it could be and what could have happened, there is no way it was delivered or that it was stolen from the porch, i was there all day, any thoughts? thank you.