Trade in [Edited: "Inflammatory"]

I was trading in my old phone for a $$800 credit towards new phone i chatted before i even did this to make sure id recieve the credit they said as long as my phone was in good shape no cracked screen no missing buttons turns on/off charges id recieve the promo no problems so i did got the new phone sent my old phone back which had nothing wrong with was in great condition then 2 and a half weeks later i recieved my trade in phone back in the mail with a paper that said ineligable due to damage i checked it over turned it on and off and NOTHING is wrong with my phone tried contacting them they couldnt tell me what was damaged about it and that someone will call in 24 hours to resolve no call the next day so i called back same thing no answers someone will call in 24 hours next day no call same freaking thing called back finally gave me a case number and said ill recieve a call been a week still no call guess this is their way of scamming people thinking their gonna get a great deal and then they decide nope now im stuck paying in full for a phone that i shoulda had an 800 dollar credit on [Edited: "Language"] Xfinity u need to do your customers better than this