I recently received a "snail mail" from a customer who had been trying to contact me through the "Contact Me" page on the site. I had not received any of his communications and then I realized that I could not remember getting any "contact me" emails for some time. Three or more weeks it turns out.
I contacted Squarespace, who hosts my site, and told them of the problem. After a few tries at fixes, I think we have it taken care of. If you have tried to contact me from the middle of April to the middle of May, 2016 and I have not responded, I apologize. I was unaware of the problem until it was brought to my attention. You don't miss emails you don't get.
When I receive a question or comment from a customer through my "Contact Me" page, I try to respond within a day. I have had a few customers whose emails have bounced back to me when I have responded, and at that point, there isn't much I can do. But that's pretty rare.