I've checked the logs and nothing is found, nobody is experiencing this bug anymore it was fixed a while back. Because of the amount of residents you have the tax should be more than others, type /towny prices and check the daily upkeep. Also, recently we increased the size cap so be careful in case assistants are claiming land.
To help us fix further issues with your town do the following:
Every day before you log out note down the following:
Amount of Residents
Money in Bank
and Land claimed
Log all those for a week, if this still occurs then I will look into the problem further and refund you.