1. Credit record is damaged: overdue repayment will lead to negative impact on credit record, which is an important reference factor for applying for a credit card.

2. Decline in credit score: overdue repayment will lead to a decline in personal credit score. The lower the score, the harder it is to get a new credit card.

3. Strict bank review: The bank will check the applicant's credit record when approving the credit card application. If the amount of overdue debt is found to be high, the application may be refused or a lower limit may be given.

4. Raise interest rates and fees: Even if the credit card is approved, banks may raise interest rates or charge higher annual fees for overdue debts.

Summary: The overdue IOUs of more than 20,000 yuan will have a negative impact on the use of credit cards, including the impact on credit records, the decline in credit scores, the difficulty in applying for approval, and the increase in interest rates and fees. It is recommended to repay the loan in time and maintain a good credit record.

Extended data:

Overdue repayment is regarded as a bad behavior in China's credit system, which may lead to a stain on credit records. According to Article 1 12 of People's Republic of China (PRC) Contract Law, overdue repayment may face liabilities for breach of contract and legal disputes. Therefore, it is very important to abide by the credit agreement and repay on time.