Riku is a free and open-source software that lets you collect responses from forms on your site. Forms to:
Point your forms to Riku:
<form action="https://riku.miso.town/submit?user_id=1" method="post">
...
</form>
...and retrieve all the responses on the web interface or via the atom feed.
Questions? Send me an email at m15o at posteo dot net.