I think they have always replied to me (as a paying customer). Now, whether their reply has any relevance to the question I asked, let alone solves my problem, is another issue entirely. I have at times wondered if they just have a random reply generator that doesn't look at anything except the subject line of the request.

Not unless you work for google.

They also take action if you can get your question/complaint to the HN frontpage..

Rarely if ever, AFAIK.