drawn position

Hi, kinda new to the forum since this is the first time i am checking it so if this is in a wrong subforum please move it to the appropriate one.

I was playing a game (link http://www.chess.com/livechess/game.html?id=238132321# ) and as we were playing his time ended. I had King and Bishop, he had King and Rook. Computer ended it in a draw because it said i had insufficient material. Though i know for a fact as a chess ref that this is not correct, i have enough material to checkmate my opponent (My Kc1, Bg7 His Ka1 Ra2), since his time ended it is a win for me according to FIDE rules of chess, so i was wondering why i didnt get the win. Also i noticed after playing the same opponent again that he gave my opponent 0.5 but he gave 0 to me, which also doesnt make sense.

he could just block your check with his rook

You fell victim to the chess.com rules based on "not trying to win by normal means" (FIDE) and "insufficient losing chances" (USCF).  Since these are claimed draws that are partially dependent on an arbiter's judgement, it isn't really possible to claim them in an online setting.  As a compromise, the "insufficient material" rules were expanded (I don't recall the exact conditions, but you can probably assume that any position where the person with time has only a single minor piece will apply).  It is unfortunate that they still call it an "insufficient material" draw when it is another type of draw, as it sometimes leads to confusion such as yours.

King and Bishop alone can not mate a lone king...yes, you can concoct a perfect scenario where if they help you, your K+B would beat a K+R, but that would require your opponent helping you out.  If you had a pawn on the board, anywhere, when his time ran out, you would get the win.

this is checkmate

this is not

Yes, its late and im tired, you guys are right, thanks! Though that does not clear why it had 0 to me and 0.5, but it doesnt really matter i guess.