Does the questioner want to ask about "the reason why the overpayment on CCB credit card cannot be transferred and the balance is insufficient?" and a handling fee is required. According to the relevant information of CCB, if the credit card limit is insufficient to cover the transferred overpayment amount and handling fee, an insufficient limit will be prompted. CCB prepayment refers to the repayment of excess funds by CCB credit card customers or the amount stored in the credit card account. The amount that needs to be paid when there is excess funds, and relevant handling fees will be charged for this part of the money.