Ravi Are you seeing the card in the Wallet app from Apple or in your bunq app?
When it is in your Wallet app, you’ll need to delete it in Settings - Wallet and ApplePay, then select the appropriate card and scroll down to the option Remove this card.
When it is in the bunq app, you’ll need to freeze the card and then permanently deactivate it. It will be stored in you archived cards. When it is already greyed out, you’re fine.