Legal analysis: 1. If the overdue repayment is still overdue, if the overdue payment and other corresponding liabilities for breach of contract are stipulated in the IOU, the debtor may eventually bear liquidated damages other than the principal and interest. 2. If the creditor still fails to repay after filing a lawsuit with the court, it may affect the debtor's credit and be included in the "blacklist". This will bring inconvenience to the debtor's loans and travel in his future life. 3, simple private lending is generally not enough to pursue criminal responsibility, but if the debtor is for the purpose of illegal possession, using fictional facts or concealing the truth to defraud a large amount of public and private property, it may constitute a crime of fraud and be investigated for criminal responsibility. Generally speaking, the basic structure of this crime is: the perpetrator commits fraud for the purpose of illegal possession, and the victim has a wrong understanding. The victim disposed of the property based on a wrong understanding. When the actor obtains property, the victim suffers property losses.

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

Article 671 Where the lender fails to provide the loan on the agreed date and amount, thus causing losses to the borrower, it shall compensate for the losses. If the borrower fails to collect the loan according to the agreed date and amount, it shall pay interest according to the agreed date and amount.

Article 676 If the borrower fails to repay the loan within the agreed time limit, it shall pay the overdue interest in accordance with the agreement or the relevant provisions of the state.