Costco is doing its best to resolve continued problems after transitioning from American Express to Visa credit cards. The decision was announced in June: 11 million customers would now have Citi and Costco co-branded credit cards, and American Express would no longer be accepted. Issues started early with Citi CEO Michael Corbat addressing questions on an earnings call in June. On the call, Corbat admitted that Citi received a high volume of customer calls:

"We're working through that. We're gaining on it. We're very focused on it. We've got a lot of resources deployed against it, and it's something we can fix in the short order."

Today, customers still have trouble getting through to the call center, and the situation has worsened. One customer posted a screenshot of his phone showing a call that lasted 1 hour and 43 minutes. Others complained that they received an incorrect card or none at all, and automatic payments were stopped.

To make the situation worse, Citi sent emails to some Costco members by mistake. The email should have gone to people who let their memberships expire, so customers thought their accounts had been hacked. Citi spokesperson Jennifer Bombardier focused on the size of the conversion:

"With a conversion of this magnitude - one of the single largest portfolio conversions in history (11 million cards) - and a brand as beloved as Costco, call volumes were unprecedented," Citi  told Business Insider. "With a portfolio of this size and eight months of pent up demand during which time we couldn't address questions on the new product or existing accounts as the portfolio was with a different issuer, the call volume was groundbreaking as of June 20th."

In an FAQ on its website, Costco answered common customer questions.

Discussion Starters:

• Who should take the blame for these problems? How can each company explain its role without damaging the partnership and the other's brand? 
• Review Costco's FAQ. How helpful do you find the answers? What else could the company include on this page?