A lot of on-line retailers do have forums. Kustom's is the only one I know that has a "Rate our Service" plunk in the middle. And if you do criticise anything, you don't get banned!
What usually happens funnily, is that they come on to the forum to complain (they are usually very mild complaints) but don't contact the company first.
Other members then post to tell the buyer to do so and Kustom sometimes post on it as well! And it all gets sorted in an instant.
And that's the way it should be.