Ahmed Taha Hi 👋 there,
If the Mastercard you have says Credit on it, then the merchant will treat it as any Credit Card.
The amount will be deducted immediately from your linked sub account and if funds are available, bunq will accept and confirm the payment to the merchant.
You can not basically spend more than what you have available on your account.
bunq dies not offer credit as part of its business.
Have a great day 🌈
GG