The fault affected Visa cardholders at Föreningssparbanken, one of Sweden’s largest banks. All customers who had used their cards on May 17th had their purchases from that day debited from their accounts again.
The fault was down to Visa mixing up their files for 15/7 and 17/5, and sending the file for 17/5 to Föreningssparbanken for a second time.
According to Expressen, Föreningssparbanken has three million customers with credit or debit cards, but it is unclear how many of these cards are Visa.
A spokeswoman for the bank told Expressen that it hoped that all customers would have been refunded by Thursday evening, and added that it would not have any effect on interest payments.