If the old Lai doesn't pay back the money, the creditor can take the following measures:
 1. Negotiate and sign a repayment agreement to clarify the way and term of repayment;
 2. Go to the court to apply for a payment order or bring a lawsuit;
 3. If it is still not returned after the judgment, it may apply for compulsory execution.
 [Legal Basis]
 In Article 2 of the Provisions of the Supreme People's Court on Several Issues Concerning the Application of Law in the Trial of Private Lending Cases, when a lender brings a private lending lawsuit to the people's court, it shall provide evidence of creditor's rights such as IOUs, receipts, IOUs, and other evidence that can prove the existence of the legal relationship between lending and borrowing.
 The people's court shall accept a civil loan lawsuit filed by the party holding the creditor's right certificate if the creditor's right certificate, such as the receipt, receipt and IOU, does not specify the creditor. If the defendant raises a factual defense against the plaintiff's creditor qualification, and the people's court considers that the plaintiff does not have the creditor qualification after examination, it shall rule to dismiss the lawsuit.