I used to make a living off of selling stuff at an incredibly low margin. The whining never stopped and I got regular calls from my vendors to "report a complaint".
Sometimes they'd tell me who was doing the complaining, and usually it was someone I considered a "friend" in the business. It always reminded me of the saying "keep your friends close and your enemies closer."
Normally the biggest complainers would be the guys who were moving ten pieces a year. Their thinking was "I'm not making any money selling this stuff and it's languishing on my shelves cause this guy is cutting my throat", when, in fact, they weren't moving stuff because they didn't have a customer base because they wouldn't lose a nickel to take care of a customer.
Long story short, in my experience, the whining fell on deaf ears, so far as the companies was concerned. They don't care any more for a whiner than we do.