I can explain your question in detail as follows:

A. Will the decline of star rating lead to the decline of credit limit? Generally speaking, banks will evaluate the credit limit of credit cards according to the credit status and repayment records of customers. Although the decline of star rating may have an impact on credit evaluation, the decline of credit limit may not be directly related to it. Whether the specific quota has dropped, you need to contact ICBC for inquiry or consultation.

B. Possible problems: Due to large-scale debt default, you may face the following problems: damaged credit record, blacklisted, unable to enjoy credit card limit increase, accumulation of interest and late payment fees, and possible recovery of arrears by collection agencies. These problems may have a negative impact on your credit status and future financial activities.

3. Summary: You overdraw and default on ICBC's credit card debt, which leads to a series of problems such as star rating decline and credit limit decline. Debt default will have a long-term negative impact on your credit status.

4. Extended information:

According to China's relevant laws and regulations and credit system, defaulting on credit card debt will lead to personal credit damage and may be blacklisted, which will affect future financial activities. In order to avoid this situation, it is suggested to communicate with the bank in time and make a repayment plan to avoid debt overdue and default as much as possible.