Really sorry to hear of your problem. I had a similar situation to my 2900MK. I was washing it when I noticed a gap in the rear between the side and the back end. Inside it was easy to see that the rear had pulled away because I could see daylight through the gap. Upon closer inspection I saw that the other side was also beginning to pull away as well!!
I took the trailer to to an R.V. collision center and had it repaired. They did an excellent job and explained the factory had used very small screws during the assembly process
so they had replaced the smallish screws with larger stainless steel lag screws and resealed the side and rear with Dicor lap compound. The repair is undetectable both inside and out. I was expecting a huge repair bill but was presented a bill of only $880.00
This repair was done at a Ford dealership that also worked on R.V.'s.