you got automatically banished by otservlist because you grew from 0 players to 200 in minutes, it got detected as spoofing because you are like the only server thats not spoofing when such a situation happens.
So ofcourse this will only happen again if you get a new IP.
The way to fix this situation is most likely:
First: set max players to 20 for 10 minutes.
Then set max players to 50 for 10 minutes.
Then set max players to 80 for 10 minutes.
Then set max players to 110 for 10 minutes.
then set max players to 150 for 10 minutes
then set max players to 200 for 10 minutes
and so on....
Why wait 10+ minutes? Because as far as I know, otservlist will recheck your server every 10 mins, and otservlist will recognize your players online score. So next time in 10 more minutes it will se score goes from 20 to 50, instead of (how you got banned) 0 and straight up to 250.