If your credit card is overdue for 20,000 yuan and you are sued, you can take the following measures:

First of all, understand the specific circumstances of the lawsuit in a timely manner, including the reason for the lawsuit, the name of the court, and the lawsuit. Case number, etc. You can obtain this information by receiving a subpoena from the court or a notice from a collection agency.

1. Prepare relevant documents: You need to prepare all documents related to the credit card account, such as bank statements, credit card contracts, repayment records, etc. These documents can help you understand past due amounts and payment status.

2. Seek the help of a professional attorney: Consult an attorney with experience in credit card debt who can provide you with legal advice and help you deal with a lawsuit. An attorney can help you clarify the facts of your case, analyze the evidence, and provide an appropriate defense strategy.

3. Research repayment options: After discussing with your lawyer, you can discuss and develop a repayment plan with your creditors to reach an agreement. Try to provide reasonable repayment arrangements and ensure they can be fulfilled on time.

4. Attend a court hearing: If the problem cannot be resolved through a repayment arrangement, you will need to attend a court hearing. Make sure you appear in court on time and have all necessary documents and evidence ready. During the court hearing, you can present your own defense and defense opinions according to legal procedures.

To sum up, when faced with an overdue credit card worth RMB 20,000 and being sued, you should seek professional legal help as soon as possible, prepare relevant documents, and discuss repayment arrangements with your creditors. When participating in a court hearing, try to provide reasonable defense and reply opinions.

Please note that the above suggestions are for reference only and specific solutions may vary depending on individual circumstances. It is recommended that you consult professionals based on the actual situation and follow relevant legal regulations.