There is two ways to make repayment on Standard card. The first method can be used to top up the card as well.
1. Use IMPS/NEFT/RTGS to make a payment to the virtual bank account ( details on dashboard ) associated with your card. The same method can be used to top up the card.
i. Login to Dashboard
ii. Click on the "Make Payment" button of Standard Card section
iii. Add the bank account mentioned in dialog to your bank account
iv. Transfer the funds via IMPS/NEFT or RTGS
2. Sign up for NACH, and we at Karbon would take care of the repayment on or before the due date. Check the below link for more details.