Not necessarily. If you apply for a credit card with a limit of 0, you can choose to deposit the money into the credit card first and then use it. This is one way to use a zero-limit credit card that will also help you increase the amount on your user's card.

If the user's credit limit is zero due to maxing out their credit card, they can no longer use it and must wait until the payment is completed before the credit limit can be restored.

Can a credit card limit be automatically reduced?

You can apply for automatic quota reduction. Users can apply to the bank to increase the credit card limit, and the bank can apply to the bank to reduce the credit card limit. However, there are very few users who request to reduce the card limit, because credit cards provide interest-free services, and users do not need to use credit cards if they do not need it.