Pay Per Call on Fb Ads

Hello, I am just starting Pay Per Call marketing on Facebook, I am sending traffic to a landing page and have a phone button call to action(A/B testing this with a quiz, then a blog post style lander). First conversion came in really expensive and hoping that the pixel learns and cost goes down.



I'm using ringba to pass back conversion events to the ads.



Has anybody had any success on Facebook Ads with