Unlevel Roof

I am noticing that the roof of my trailer seems to be very unlevel in different areas.  The main area of concern is about 18" outside of the air conditioner.  With the trailer level on the ground the roof will hold a few inches of water on the driver side of the trailer. 
Also if I step on the roof over the front bedroom area it seems that the substrait material has bowed up. 
Does this seem normal?  Who would I contact to look at this issue?  The dealer I purchased from is no longer carrying Crossroads or at least the sunset trail model. 

We had a problem with ou 07 30sk roof. When walking on it last spring while washing it, it sagged above the bedroom slide. I laid a level across the area to show the extent of the sag, photographed it and emailed the photos to Randy M. after talking to him. Randy agreed there was a problem, made me an appointment at the factory service center for early last June. They peeled back that part of the roof and repaired a sagging trusse. Only took them about 4 hours. Covered under the 2/5 warranty.