When the credit card limit is insufficient, you can indeed complete the payment by depositing cash, but this involves a concept called overpayment. Overpayment refers to the amount of funds that exceed the repayment amount on your credit card and are deposited into your credit card account. In theory, you could use the extra funds to make purchases or make payments, but that's not the best way to use a credit card. In fact, most banks will charge a certain fee for withdrawing overpayments. The fee ratio is usually between 1 and 3, and the regulations of each bank are different.

Although depositing excess payment can temporarily increase your available limit, it is not free. If removal is required, additional charges may apply. Additionally, overpayments are non-interest bearing, which means the money will not generate any income for you. When using a credit card, if the consumption amount is less than the overpayment, you will not be overdrafted and the overpayment will be deducted first.

Therefore, although depositing overpayments can solve temporary payment problems, the possible costs need to be weighed. Generally, credit card companies encourage users to spend up to their credit limit rather than deposit excess funds. When making a decision, it's best to consider your personal financial situation and your bank's specific policies.