The Dutch tax office is facing criticism for incorrectly calculating income and subsequently overcharging individuals who submitted their tax returns after the deadline. The issue affects thousands of taxpayers, with the office reportedly using inaccurate data when determining outstanding amounts. Investigations reveal the errors stem from flawed algorithms used to estimate income for late filers. Affected individuals are now required to submit appeals to reclaim the overpaid taxes, creating an administrative burden. The tax office has acknowledged the problem and stated it is working to rectify the errors and improve its processes. Consumer organizations are urging the office to proactively contact those impacted and offer full refunds without requiring individual appeals. The scale of the overcharges remains under investigation, but early estimates suggest a significant financial impact on citizens.