Legal analysis: If there are no invalid reasons such as coercion and fraud, the IOU is valid. It's just that the amount may be controversial. The loan contract is a practical contract, that is, the actual amount of prosecution! If there is evidence to prove the actual amount owed.

Legal basis: Several Opinions on Handling Loan Cases by People's Courts Article 5 If the debtor's whereabouts are unknown when the creditor files a lawsuit, it shall be under the jurisdiction of the court where the debtor's original domicile or property is located. The court shall require the creditor to provide evidence to prove the existence of the loan-loan relationship, announce and summon the debtor to respond to the lawsuit after acceptance. If the debtor still fails to respond to the lawsuit at the expiration of the announcement period and the loan-loan relationship is clear, the judgment may be made by default after trial; If the loan-loan relationship cannot be ascertained, the lawsuit shall be suspended. In the course of the trial, if the debtor leaves, his whereabouts are unknown and the loan relationship is clear, the judgment may be made by default; If the facts are difficult to ascertain, the proceedings shall be suspended.