Immediately file a lawsuit to the people's court at the defendant's domicile on the strength of the IOU or IOU.
 Prosecution process:
 1. Prepare litigation materials, and prepare the indictment when filing a lawsuit.
 2. Bring evidence and indictment to the court for filing and pay legal fees;
 3. Conduct court hearing and mediation or judgment according to the production arranged by the court;
 4. If the other party fails to repay the loan within the specified time after the mediation or judgment takes effect, the plaintiff may apply to the court for enforcement.
 [Legal Basis]
 Civil Code
 Article 675 The depositor shall return the credit money within the prescribed time limit. Where the time limit of the credit is not prescribed or clearly prescribed, and cannot be determined in accordance with the provisions of Article 510 of this Law, the lender may return it at any time; The lender may urge the lender to return the loan within a reasonable period of time.
 Legal basis
 Article 675 of the Civil Code of the People's Republic of China [Time limit for the borrower to repay the loan] The borrower shall repay the loan within the agreed time limit. If the term of the loan was not agreed or clearly agreed, and cannot be determined in accordance with the provisions of Article 510 of this Law, the borrower may repay the loan at any time; The lender may demand the borrower to return the loan within a reasonable period of time.