A couple celebrating their recent marriage engagement is now calling out United Airlines on TikTok after they got treated extremely unfairly on their flight. As a gift from the bride-to-be's parents, they got them first class tickets for their trip from London to Chicago. This is not a usual thing for this couple, so it felt like such a special occasion and luxury. Unfortunately, United Airlines came in to ruin that celebration for the two lovebirds. Once they were already seated and full of ex…