Find the buyers who pay you and the payment methods they saved.
A buyer is a person who pays you through a checkout or a subscription. Payment Labs keeps one buyer per merchant and email address, and creates it the first time you send that email in a checkout or a plan offer; you never create buyers directly. Buyer IDs start with U-.
Search buyers by email or by your referenceId to find a buyerId, then list the instruments that buyer saved with List Buyer Available Checkout Instruments. See Saved Cards and Merchant-Initiated Charges.