We're aware of an issue with Facebook purchases for all King Games and our team is on it. 🛠️ Hang tight while we fix things! You can still enjoy the game, and we'll keep you posted once it's solved.
I have noted this about two weeks ago. It is undoubtedly there to trick you into buying the UFO with your gold, which is a terrible waste. You need to be careful NOT to click the green button! Just click on the red Play button underneath!