FREE GAME How Costco returns work with Mastercard: • Costco accepts Mastercard for purchases. • Costco does NOT process refunds back to Mastercard. • When you return an item bought with a Mastercard, Costco issues the refund to: • Cash, or • A Visa debit card, or • Costco shop card, depending on store policy and manager mood. So in practice: • You buy something with a Mastercard credit card. • You return the item. • Costco asks how you want the refund. • You give them a Visa debit card. • The refund goes to your bank account, not back to the credit card.