I do small to medium jobs sometimes, but I don't have time this summer to take anything on. Don't those have warranties? If you really need repair work on a brand new raft I would think they would pay shipping to one of the repair shops in Salida or Denver.
Anyways, it sounds like a leaky valve to me. Probably needs to be cleaned or new guts put in it. Neither job takes more than 20 minutes, and you should learn to take those valves apart anyway. Next time you soap it up make sure to put a little in and around the valve and look for bubbles.