Your rating didn't change after your last game because it didn't have enough moves. The game has to go 4 moves for it to change your rating.
how are points determined

Its more complicated than that. If you post on a Mon, Wed, or Fri, and double down, you'll get 2 points for every post. If you live west of the Mississippi, subtract a point. If its raining when you post add 3 points. If your a black man, add 2 more. If its on the weekend during Feb, forget it, 0 points. WHY? The points store isn't OPEN in Feb.

third request again l won against a plyer rated higher than me by 300 pts and my rating stayed the same why

If you mean this game:
http://www.chess.com/echess/game?id=114800126
It's because it only went 3 moves. The game has to be at least 4 moves before your rating changes.
l have played games with rated player won and rating stayed the same