You can't. Credit card can't directly repay the mortgage. Credit card is used for convenience and discount, but if it is used improperly, it can easily cause various additional losses. They want to use the interest-free period of the credit card to repay the mortgage in disguise. Credit cards can't be used as repayment accounts for mortgage loans, and credit cards can't be repaid by credit lines through consumption, so they can't enjoy the interest-free period of up to 50 days.