I had a 26 Scarab and often got that exact same treatment from the dealer who claimed it was Wellcraft. As an example, my windshield was broken and it took over 4 months to get a replacement from Wellcraft! That's one of the reasons I opted for a new manufacturer to "test the waters".
I've attached a pic of the plastic pieces in question so that others can see what we are talking about. The piece is of the rear quarter of the boat just above the rub rail.
Good luck dealing with Wellcraft!