If there wasn't a limit, then an unscrupulous player could just adjourn any game he was losing and hence never lose. I think 15 is more than enough. For any games that are adjourned, first try to contact the opponent to resume the game. If you are losing any games consider resigning, or offer a draw or abort in even games. If your opponents don't reply within a week, you can message the adjudicate account, instructions are available from 'help adjudicate'. Hope that helps.