This was left in my comments ------(Your listing has been purchased by the user “RLtrading56”. You have (1) days(s) to deliver item(s) to the GamerTag:“SketchyGamer52”. Your credit will be sent and listing will be sold once the buyer has received/reviewed the item.)
To be blunt. there is nothing you can do. Gameflip doesnt cover being scammed unless the transaction takes place through their offical sales system.