Clinton's campaign responded.
Trump's campaign didn't.
AOPA 2016 U.S. Presidential Candidate QuestionnaireClinton's campaign responded.
Donald J. Trump, Republican Candidate for President
After multiple attempts via many communication channels, no response was received from the candidate as of press time (candidates were given six weeks to respond).
You're running for office. You get a free shot to speak to about 400,000 people who probably will largely turn out to vote. A hell of a lot of them are able to write decent checks to support a candidate. And it may be a reasonable bet that the majority of them are sympathetic to your party.
So why the fuck would you blow off a chance to get your message across to them?