After 2+ decades of RVing, I gave up on wasting time trying and failing to buy parts from CW. The last straw was when I tried to buy a toilet flange from one of their stores. The toilet flange, in this case was a common ABS plastic 3" outlet piece that is also used in residential plumbing. I literally couldn't get anybody to even listen to me, including a service writer and EVERYBODY at the parts counter, unless I had the make and model of the toilet. I eventually got a young lady to pull up the schematic on a common Thetford toilet, and showed her that the piece I was looking for had NOTHING to do with the toilet manufacturer, and did not appear on their drawing. It didn't matter, if you use don't have a brand and model # they literally are unable to proceed.
I then headed to another, family owned dealer down the road. Five minutes later I had my $7 part, and they had another good laugh with one of the hundreds of customers who showed up at their counter, after wasting time at CW.