Callback/Pingback URL (OfferWall) for myCred Wordpress Website

I need to set up a callback/pingback URL for offerwall (TrialPay, PeanutLabs, Paymentwall, OfferToro, AdGateRewards) for my wordpress website. I am also using the plugin, myCred. I also want to connect the offerwall to myCred. When the user completes an offer on an offerwall, the offerwall will send a request using callback/pingback, which then goes to myCred. Must be familiar with Wordpress, Offerwalls, Setting up CallBack/Pingback urls, and myCred plugin for Wordpress.