Stripe 'Card ID' - how can I retrieve this when the customer has already registered?

I already have customers signed up to the platform using both the Bubble stripe API’s and the Zeroqode Marketplace API’s, however seeing these have already signed up and credit card details logged, I have not saved the Card ID from stripe.
How can I retrieve this for existing customers (as currently I only seem to be able to retrieve their payment method only).

I am trying to use + implement the ‘create a subscription’ API plugin and this asks for / requests a ‘Card ID’ value which I do not have saved.

  1. I need to link a customer to a seller

  2. then create a subscription (previously I only sold products, implementing this means I have to collect past CC information such as Card ID).

Any suggestions welcome here as I may be going in the wrong direction!!