Keystone RV shower drain not attached to P trap factory extreme water damage and black mold Goshen, Indiana

We have a 2010 Keystone Retreat that is permanently placed on a site and skirted.   A repairman was hired to locate a leak in the kitchen.  When he went under the trailer he noted another "minor" leak coming from the moisture barrier under the bathroom.  When he cut the moisture barrier the water poured out of the insulation.  Upon removing the insulation he found that the factory (Keystone) had not attached the P trap to the shower drain.  Fortunately we do not live in this unit full time and spend only 2 to 5 months a year, as the shower had been draining directly onto the insulation was the time we purchased it three years ago.  When Keystone was confronted with this, they refused to do anything about it as it was "out of warranty" and wanted to know "why it had taken us 3 years to find the leak."  Who in their right mind would go under their unit, cut the moisture barrier, remove the insulation, looking for leaks.  Had this leak manifested itself earlier, we would have found it, as we are on a concrete slab and it would have run out from under the trailer.  We now have had to remove the moisture barrier, insulation, have it treated for black mold, and eventually have the insulation replaced as well as the moisture barrier. 
As an aside, I am a cancer survivor struggling with my breathing and this has created an additional problem necessitating my sleeping on my screened in porch. 
Keystone feels no responsibility for what has occurred.