I've only had a good experience when calling "excecutive customer service". I don't have the number handy but you can find it easily on google. They're nice, respectful, and when they don't know the answer say so instead of making things up.
I haven't personally had an inssue resolved here, but in all fairness the crew on the forum seem fairly responsive as well. As most of the final resolutions seem to occur of PM it's hard to say if they're effective, but i imagine there would be angry customers calling them out here if they weren't.