I've had this extension installed for at least a year now. It frequently pops up and tells me I can get X% cash back. It does this at checkout. I click the button to get the cash back. It reloads the page. I can see they have appended affiliate information to the URL. I complete the checkout. Never get cash back. No adblockers are enabled. It's either a deliberate scam or incompetent developers. Either way there are other cash back companies that I'm moving on to that offer lower cash back, but actually give it every time.