This is a snippet from their "Terms" page. It appears you are using their services at your own risk. Think twice before using them as a publisher or as an advertiser.
"The information contained in this website is provided on “as is” basis and for general information purposes only. The information is provided by Propeller Ads and while we endeavour to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the website or the information, products, services, or related graphics contained on the website for any purpose. Any reliance you place on such information is therefore strictly at your own risk."