Anyone using Adskeeper ad network

Hello
Does anyone using Adskeeper ad network for monetization of their websites? few days back they contact me via mail and asking to work with them as you can see in the screenshot. Currently am using Google AdSense and Taboola and most of my traffic comes from the West.

So here is my doubts are they legit
can I use Adskeeper with adsense (Coz Adsense don’t allow some network ads to show their ads along with adsense)
and are they really paying $9 CPM