Last Monday was an important day in retail history, and we’re not being sarcastic: it was the day that Costco switched its credit card acceptance policy from only accepting American Express to only accepting Visa. The transition didn’t go smoothly for some members, and national competitor Sam’s Club decided to take advantage of the confusion and try to win over some of those members. Unfortunately, some employees didn’t know about this.

Reader Megan decided to visit her local Sam’s Club, bringing her two young kids along. Only no one at the store had heard about the promotion. “The card checker at the door was rude, told me I was at the wrong

store, and was absolutely incredulous that Sam’s would ‘just let people from Costco in’,” she wrote to Consumerist. “I had to go wait in line at member services and actually had to show someone an ad about the promotion before they would let me in.”

That was just getting in the door to look around. Megan was under the impression that Costco members could make purchases, too. That also took some wrangling and the assistance of a few employees, and she had to pay a 10% non-member surcharge. “I didn’t even know that was a thing,” she grumbled.

Megan wasn’t alone: other shoppers shared their stories on the Facebook post where they originally learned about the promotion.

We checked with Sam’s Club, and they confirmed:

The promotion is real.

You can get in the club with your Costco card.

You can make purchases and should not have to pay the 10% non-member surcharge, like Megan did.

The promotion lasts through July 4, 2016.