I'm thinking that the dealer needs to step up and finish his part of the deal. Removing stickers means all of the sticker--not just the top leaving the glue residue. I question if it was washed as washing don't leave black streaks. Normal rain run off from roof causes black streaks. It should not matter if it was a "internet special." If part of the deal was sticker removal and a wash job then it should have been done and done correctly.
RV dealers are not like car dealers and a sparkling shinny waxed rig will vary between dealers. Some do and some don't. You may not have "shinny" in your specific deal. Randu