Ask HN: Tool for ad-hoc collection of answers from clients?

I try making it easy by asking questions one by one in a numbered list and keeping it to no more than 5 questions per email, but inevitably, I never get all of them answered.

This is taking a huge toll on my time just trying to wrangle getting answers to simple things I need in order to complete my work.

I think email is just not working for this client, and I believe there must be a better way.

I'm wondering if there is something with a user flow not unlike survey sites such as SurveyMonkey but is specifically targeting to ad-hoc answering. My client may not have all the answers available at a given time, so I want them to be able to revisit the page and edit previous answers and provide answers to questions they have not answered yet.

The important thing is that I believe just having a wall-of-text list of questions is what is not working for my client, so a more expanded workflow with a tally of # of questions answered vs not answered would be ideal.

I've also tried just asking one question per email -- does not work either.

Is there an existing tool that the HN community uses?

One question per email?

Something like Trello, using each card as a question, and three columns (unanswer? re-ask? finished?)

--

In case the questions need to be in a block because they are related and need some background, try to make each question easy to distinguish. Like

* First question?

* Second question?

* Third question?

(I think that in some case I number them so it's 100% clear, but I use this with coworkers that can't fire me :) .)