Subscription issue if a customer have two or more cards

[bahung1221]

Sorry for firing the issue here, but I don't know where to push it.

Currently, when creating a subscription through Payjp (monthly/yearly payment) we only can specific the customerId and the planId without cardId.
The scenario is if a customer has two cards name card A and card B, then he wants to buy a subscription with card B but the default card is card A, the problem will occur since he will be charge by card A instead of card B.
I know that we can create different customerId for each card but our system is running on production 4 years ago, so we can't remove all old cards of our customers.

So please help me to figure out if there is a valid solution in the solutions list below:

• Create a new customerId list from old list cards. We already stored card id (car_325xxxxxxxxxxxxx) in our DB, so can we use the old card id list to create a new customers list?
• Create a new customerId list and a new cards list from old list cards?
• Or create subscription by cardId instead customerId?

I read all the Payjp API docs but can't find anyway...
Thanks and best regards.