support question

Hi, I bought support today, but didn’t get a license key. My question is to styles for a plugin I use.
Hello,
I have troubles with a plugin, that shows real estate objects on the page of my customer. The objects are described on another platform and should then be displayed on the homepage of the real estate company. Unfortunately I can neither change the background color on the resulting page nor the font color. The people who provide the plugin, informed me that it does not work on all themes. I tried another theme and it actually worked. But I would like to stick with Enfold. I tried to work on the style.css of the plugin files, but no change.
Any ideas, how I could get it going?
Thanks!