@rabol I am sorry, I am just showing you what I see and how I manage to make it work. Checked the Billable trait and in order for the card_brand to have any value, the user has to have a default payment method, otherwise it just returns false. That's it.
Trying to help here, but obviously you don't like my answers.
No this is not a trick:
$user->updateDefaultPaymentMethod($user->paymentMethods()->first()->id);
it is an example on how a user default payment method can be set..
Will this be more of a helpful example:
$user->updateDefaultPaymentMethod("pm_asdsadsa");
Then I will be asked what is the string in there..
Or I remember, you want someone to do the complete job for you.. But we are programmers that's our job, to find a way out, using documentation, trying out and debug..
I am out of here :) Sorry once again if I offended you somehow, not my intention in any shape or form.