I just dealt with both GD and Dexter about a bent axle. I asked GD for a report number, which they provided. I then contacted Dexter. They said fill out the warranty form online. Include photos of the axle ID tag, the VIN tag for the trailer and a picture of the damage. I included the heavy wear on the inside of the tire. In addition, I provided what the RV shop which is doing the axle replacement told me. In his opinion, he was more than 95% positive the axle was bent. I happen to be fortunate the shop has dealt with Dexter for years and he was their area repair guy until they changed how they handled things.
Dexter has shipped to the shop a new axle (complete with springs, brakes and bearings), which will be changed next week. I also ordered up a new set of shackles and wet bolts/brass bushings from Amazon (Morryde 2.5 inch) which can be returned if not needed. Jayson suggested doing that in case we needed them. Also, if the axle is not being returned, I thinking about saving the brake assemblies (as long as they are in decent shape) in case they're needed in the future.