Legal analysis: People who have been cheated to write IOUs can bring a lawsuit to the court within one year from the date when they know the reasons for cancellation, and apply for cancellation of IOUs.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 148 If a party causes the other party to commit a civil juristic act against its true meaning by fraudulent means, the aggrieved party has the right to request the people's court or an arbitration institution to cancel it.

(1) The party concerned fails to exercise the right of cancellation within one year from the date of knowing or should have known the reason for cancellation, and within 90 days from the date of knowing or should have known the reason for cancellation; (2) The party concerned is coerced and fails to exercise the cancellation right within one year from the date when the coercion is lifted; (3) After the parties know the reasons for cancellation, or explicitly give up the cancellation right by their own actions.