At Camping world you paid for an installer, not a mechanic. You would be hard pressed to find one of them guys to understand axle geometry never mind to diagnose it. You had a pre-existiing condition and as I diagnosed in a previous post, it's time to replace the leaf springs. Personally, I would not get a factory spring but instead go to a trailer repair shop and have them replace the leaf packs (using combined measurements and trailer weights to design the proper rate springs). Keep us posted.
*Current: 2005 Ford F350 Crew Cab Dually 6.0 diesel 4x4*
*Retired: 1987 F350 Crew Cab Dually 6.9 turbo diesel
2007 Forest River WildCat 32QBBS