This might be one of those grey areas especially if there are no annual fees to use the card. If the only fees they earn are the per transaction fees paid by the merchant and interest charges you pay if you do not pay the bill in full each month which you can avoid, it may not fall under the "selling goods or services" or "qualifying you as a sales prospect for a third party" provisions of the Telephone Sales Rules. Be interesting to run this past the DNC Office for clarification as to whether or not they are required to screen against the DNC list before calling.