If there is only one card bound to the account:
If there is only one card bound to your account and you still have ongoing orders, you will not be able to delete your card information. Please note that every account will require at least one card to complete the payments. You will not be able to delete this card unless you have added another card and set the latter as "Primary".
If there are more than one card bound to the account:
If the card is not set as "Primary", you can delete the card information in the App. "Me"＞"Payment method"＞tap the card＞"Delete"