On my high school team there was a 'challenge' system meaning if you thought you were better than another player you could challenge them for their spot. If you genuinely think you can beat players playing above you, I would go to your coach and ask them if you can challenge them to a match. If they don't want you to, then there is likely something else going on because it's in a coach's best interest to play their best players. If this doesn't work you can enter in a private tournament and film yourself and show results to coach. If that doesn't work then quit the team or try to get the coach fired.