Can you clarify? Where are they taking half the page? Is that on mobile or a vignette ad that you are referring to?
It's possible to adjust the ad placements directly through your dashboard.
You can go to Ezoic Ads -> Ad Configuration to disable ads in various locations. For example, you can use the exclusion filter to remove ads from lists and specially formatted boxes. That page also allows you to adjust ad density and minimum number of words per paragraph.
Vignette ads, which are pop-up ads that appear in between internal pageviews, can be reset through Ezoic Ads -> Ad Types.
There are also other ad restrictions you can enable, e.g. Disable Ads by Page, Ad Categories, Max Ads per Page etc.
If it's just an issue on one page instead of sitewide, you can use the Ezoic Chrome extension to make adjustments.