The ONLY thing to do at this point is take it to a good frame & axle shop with experience in travel trailers. Get a full inspection done and a report made including photos. Then send it to Keystone and the dealer.
Have been through something similar in the past and initially got the party line "it's within spec." response. Knew darn well something serious was wrong. Then went to a gov't certified frame & axle shop and got a resolution.
You might try and see if there is a better person up the food chain at Keystone to send a report to. If you have an RV show coming up, see if you can find a factory rep. to talk to and find a contact at the factory.
Don't take no for an answer. Good luck.
Edit: If you bought it from Camping World, I wouldn't count on much help. You might also call the axle manufacturer, whoever your axle label says. Maybe even Lippert, but not without some good evidence first. Going to a scale and getting a weight ticket might help too.