doesnt make any sense

i am complaining at the feedback i recieved which does not make sense at all. first i had app**** for vehicle finance in sep which was granted. and now i want to trade in my vehicle i get denied because one of my accounts are not handled properly.which one i ask ? i get told you need to contact transunion. fine so i call transunion and they say all my accounts we well kept. and so i ask how can they approve me 4 months ago and now i am denied. it does not make sense, please can somebody provide valid reasons as to why i cannot get finance.