How to increase the height of the embedded survey on our website

We have a survey embedded on our site, but we can't figure out how to increase the height of it. It's only displaying the first question and the user has to scroll through the survey. The company told us to:

- Here is a command you can paste in the source code of the website,

Here is a command you can paste in the source code of the website, #DIV_7070887,iframe{height:800px !important}

Here is the code we embedded on the page: (I changed the URL's) 

                
<script>
EMBED_PARAMS = {};
EMBED_PARAMS.surveyID =7070887;
EMBED_PARAMS.domain ="//www.questionpro.com";
EMBED_PARAMS.src ="//www.questionpro.com/a/TakeSurvey";
EMBED_PARAMS.width ="100%";
EMBED_PARAMS.height = null;
EMBED_PARAMS.border = "hidden";
</script>
<div id="div_7070887"></div>
<script src="//www.questionpro.com/javascript/embedsurvey.js?version=1"></script>
            

Any thoughts?

Can you share link to embed survey on your site?