Communication from constituents does matter, from what I've seen. One problem is that as the jurisdictio n gets larger, the number of concerns rises. Many times there are competing citizen concerns, and it may seem like one's concern is lost. I find that some well made points can help firm up a wavering position. I do agree that a firm position held by an office-holder is unlikely to be swayed by constituent comments, but I've seen that happen, too.
Our local town doesn't even believe in enforcing codes against the power company (they claim it's not their job), how can I trust them to be competent enough to enforce anything else?