Yes, "kamei" is "affiliated" or "participatory" and "keiyaku" is "contract" but the term you're looking for here is best translated as "affiliated card company". This refers to a credit card issuer who is not the main company or bank (primary issuer) but instead a secondary or derivative company that has an arrangement (keiyaku)with the main company or bank. Trust me, i used to work for VISA (2 years) in the Lost/Stolen card department and i saw this term all the time. HTH.