When was your payment deadline? Have you tried contacting him and/or have you received any communication from this manager? Have you played with them in the past and never had any problems? Has been actively participating every week?
Basically it depends on what you have or haven't done so far. But alerting him that if efforts are not made to resolve this it will result in his team being locked until payment is received and lead to forfeiture of his play-off spot. You have to think of what is fair for all the mangers, removing him and finding a new manager may be your only option if these efforts don't work..