lordgrim97

[bitter lichen]

If you try to just update the Subscription quantity again (calling another Update API), what happens then?

[tropic lake]

it will again try to generate the invoice and record payment for that.

But the issue is, I don't know to what quantity I need to revert to.

[bitter lichen]

Before the subscription is updated first time, you can save its quantity somewhere to reference to, no? Or you can look at the customer.subscription.updated and see the previous attributes

[tropic lake]

let's say we have the previous quantity.
Updates will be as follow:
S1 - I1 (quantity 5) - $50
S1 - I2 (quantity 10) - $100
now, payment to invoice I2 get's failed, $50 will come in Credit balance (which never got paid)

Revert
S1 - I3 (quantity 5) - $0

now next invoice will try to use the $50 credit balance which never got paid.

[bitter lichen]

I see, I think you would want to adjust the credit balance to undo the side effect of I2 too