Costco's credit card switch-over has been a troubled one. Image source: Citigroup.

You can't make an omelette without breaking a few eggs.

Even though Costco (NASDAQ:COST) had more than a year to plot its switch from American Express (NYSE:AXP) to Visa (NYSE:V), it was inevitable that problems would occur due to the sheer volume of customers involved. No amount of planning can make a move involving roughly 11 million cardholders go completely smoothly, but the way this switch was set up practically asked for problems as there was no overlap period between the old American Express TrueEarnings card and the new Costco Anywhere Visa card provided by Citigroup (NYSE:C).

On June 19, customers had to use their AmEx and then on June 20 those cards went dead, and the warehouse chain stopped accepting American Express altogether.

That abrupt change left room for all sorts of problems. Some consumers did not get their new card in the mail (or they did and it was thrown away without being opened). Others had trouble activating their new cards, and a third group -- American Express users who did have the Costco rewards card -- simply weren't paying attention and were blindsided to learn at checkout that the chain now only accepts Visa credit cards.

The confusion has led to longer checkout times in stores, long wait times for customer service from Citigroup, and discontent among some customers. Early problems with the switch led to 1.5 million calls to Citigroup, according to a spokesperson for the card issuer.

It may have been an expected situation, but it's a bigger mess than was planned for that Costco and Citigroup are working to clean up.

How big is the problem?

At the root of Costo's problem is the fact that no amount of mail sent to consumers guarantees that they will take action. It also likely did not help that many people use automated payment methods to settle their credit card bill each month making it so that even messaging in the bills about the change would likely be missed.

At least partly because of that, and the general lack of messaging or signage in Costco stores about the switch, only two-thirds of the new Visas had been activated as of June 23, Costco CFO Richard Galanti told Bloomberg. In addition, the CFO acknowledged to the news service that 180,000 customers (a tiny fraction of the 11 million total) did not receive a new card at all due to mailing address issues.

"We don't take it lightly, but we are trying to convey to people that this was well planned out," he told Bloomberg. "It is not without its issues but we are addressing them and working hard to do that."

In addition to problems getting cards, some consumers have complained on social media about wait times for Citigroup customer service being measured in hours, not minutes. Galanti acknowledged that as well, saying that the card issuer has added new customer service reps and waits have dropped to less than 10 minutes.

Costco customers react

While Costco's customers have made a lot of comments on its Facebook page about the credit card problems (in many cases under unrelated posts) a lot of them are surprisingly accepting.

"Everyone needs to realize that with a switch over this large, there are bound to be problems....take some deep breaths, chill out and remember that if/when you get someone on the phone in the customer service department....KEEP YOUR COOL! Soon enough you will be able to charge stuff at Costco to your hearts content," wrote Tanya Murphy under a link to an insurance partner the chain had posted.

That touched off a spirited discussion, which was polite by internet standards. Not everyone was happy, but the tone, as it appears to be in much of the discussion on Costco's page, remained civil.

"Really shocked that Costco and Citi did not anticipate how many people would be calling in with questions about the CC changeover and didn't hire extra people temporarily. Disappointed," wrote Roberta Gale.

Even people angry at how Costco operates kept things polite.

"I think it's crazy that Costco forces their customers to use a specific credit card, signals anything but customer-centric mindset," wrote Anders Spatzek. "I guess it's their prerogative, it's mine to decide where I shop and I guess I won't be renewing my membership."

Costco will get through this

While the warehouse chain finds itself dealing with angry customers now, it has a lot of built-up goodwill to help it get through this crisis. Costco topped the specialty retailer category in the most-recent (2015) American Customer Satisfaction Index retail report, just as it did the previous year.

This credit card conversion -- the biggest one in U.S. history -- may have been rockier than expected, but the company has made big progress in fixing its problems very quickly. Costco will lose some members over this, but ultimately it will get past these issues.

Method of payment is not why most people shop at the warehouse club. Switching to Visa (for a card with better rewards) ultimately won't have a long-term negative impact on the company. In fact the worst appears to be over. This change will continue to cause problems for weeks, maybe months, but the number should steadily decrease, making it easier for Costco and Citigroup to solve any lingering concerns.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.