$3,000.00 for just the decals is absurd! Many of have had the same problem. Painting the caps with a base coat/clear coat finish is the only cure. There was no uv inhibitor in the gel coat. You can buff and wax forever it will keep coming back. Mine cost $1500.00 to paint the front and $1050.00 to paint the rear. Manufacturer supplied the decals and they were installed by the paint shop. Find a truck/bus shop and get some bids. They will have a large enough paint booth. Forget going to an RV dealer. They usually send them out and mark up the price..Good luck.
B.O.