Unfortunately such childish behavior (from all age groups) is all too common. Chess.com is aware of it and has taken action according to staff. Note that live pairings now take such crappy behavior into account:
http://www.chess.com/forum/view/livechess/new-logic-for-auto-pairing-and-seek-graph
Ah, thank you for these news. I find this new pairing criteria is perfect. 
The game http://www.chess.com/livechess/game?id=858056519 is recorded as being lost by myself on time but my screen showed my opponent losing on time. What gives?
Oh! So there's nothing I can do about 'losing' a won game :(
There are 3 kinds of players that I hate:
1- I can win so I disconnect. At least, with this group you only have to wait a few seconds.
2- Even worse, the ones that don't even disconnect and just stop playing until the time runs out. Rude! Rude! Rude!
3- The ones that propose a stalemate after a major blunder just to quit immediately after you reject the offer.
I wonder what happened to sportmanship
I don't know if its because I've finally moved my rating, and the slightly higher rated players are more inclined to do it, or if the problem has really gotten worse in the last month of so.
I understand connectivity issues happen (I've given away at least one or two games thanks to my Australian quality internet), but those who disconnect from a losing position are a minor frustration. I've been blocking and reporting recently, but it seems I need to do it every second game. I'm worried I'm going to show up as a serial complainer!
We all know about that kind of people that everytime they make a big blunder or when they are just losing they disconnect from the game and leave you there waiting for them, until the time finishes.
Are they aware that when they disconnect they will lose the game anyway? What's the point of acting like this?
I was playing now a game and they did it again. This is really discouraging.