Costco’s Transition to Visa Cards Riddled With Problems By STACY COWLEY Citigroup, which is issuing the new Visa cards for Costco, has logged more than 1.5 million customer service calls on them. http://www.nytimes.com/2016/06/24/business/costcos-transition-to-visa-cards-riddled-with-problems.html?ref=business