Caused of an Overbooked Flight

Supposedly, Jeffrey’s flight was on 10^th of January, he’ll be boarding of NorthWest Airlines and got there around 20 minutes before the plane on board. Sad to say that attendant in the ticketing both wont allowed him to go on that plane. It was really their fault, they didn’t even emailed them and explain the said uncertainties. How come there are airlines that just don’t care on their customers? And this is not the first time happened to him, last year this problem happened to him and still the airlines didn’t make up anything for their customers. He went home and the ticketing attendant assures that he’ll get on the same time flight but just moved his date from 12^th to the 13^th. My excitement on this was prolonged because of what happened.. Poor Jeffy...