Why can't one pay for past due subscriptions with microsoft account balance!?

I have link for you: https://support.microsoft.com/en-us...unt-pay-for-a-past-due-microsoft-subscription

Gift cards, subscription cards, or your Microsoft account balance can't be used to pay for a past-due subscription.

because you can't use account balance to pay a past due amount. https://support.xbox.com/billing/xbox-subscriptions/pay-past-due-balance-on-xbox-subscription

If you ended up in a past-due situation, that is the reason why it will not resume by just adding credit to your balance. Unfortunately gift cards, subscription cards, or your Microsoft account balance can't be used to pay
for a past-due Subscription so, to settle that, you will need to use another payment method or eventually contact support to see if they can manage that.

https://support.microsoft.com/en-us...unt-pay-for-a-past-due-microsoft-subscription

https://beta.support.xbox.com/contact-us

Hi,

you can't use Gift Cards or the Microsoft balance for subscriptions.

Due to this, you should use a credit card (the same or another one) or one of the other valid payment methods to pay a past due, as explained here https://support.xbox.com/billing/xbox-subscriptions/pay-past-due-balance-on-xbox-subscription.

Here is some support information that can help you get your account current.

"Gift cards, subscription cards, or your Microsoft account balance can't be used to pay for a past-due subscription."

https://support.microsoft.com/en-us...unt-pay-for-a-past-due-microsoft-subscription