Anyone used RevMob? Setup Help.

 import System.Collections.Generic;
 
 private var APP_IDS = new Dictionary.<String, String>();
 private var revmob : RevMob;
  
 function Awake() {
  
     APP_IDS["Android"] = "53ac8c56382eddda069ed27c";
     APP_IDS["IOS"] = "53ac8c56382eddda069ed27c";
     revmob = RevMob.Start(APP_IDS, this.gameObject.name);
     
 }
 
 function Start(){
     FullScreenAd();
 }
  
 function BannerAd () {
      var banner = revmob.CreateBanner(RevMob.Position.TOP, 0, 0, Screen.width, Screen.height/7);
     banner.Show();
 }
 
 
 function FullScreenAd () {
  
     var fs = revmob.CreateFullscreen();
     fs.Show();
      
 }

Hello, I am just trying to integrate RevMob into my game to display a full screen advert. currently BannerAd() works fine producing a banner at the top of the page but FullScreenAd() does nothing. When the full screen function is ran the debug log confirms that RevBob scripts are doing something but no ad has popped up.

Any help would be appreciated. Thank you.