British Airways passengers have expressed their anger at being unable to get through to the airline following the confusion over cancelled flights. BA pilots are due to strike on 9, 10 and 27 September, but BA also told customers with tickets booked on other days that their flights were cancelled. The company admitted on Saturday that it had told some passengers, by mistake, to rebook or get a refund. It said those who booked other flights could claim the extra costs back. However, it has not commented on how many customers have been affected, or the reason for the error. BA also said it received nearly 40,000 calls in the first 24 hours and was working around the clock to help sort people's problems. After initially sending one email informing customers of cancellations and then telling them to rebook or seek refunds, BA then sent a second email to some people saying their original flights would go ahead as planned. But in the second email, passengers were not given a link to automatically rebook onto their original flight, meaning they had to contact BA directly. Some customers say they have spent hours trying to get in touch with BA's customer services without success. In response to one passenger, a BA representative said: "We're extremely sorry that you're having difficulties trying to rearrange your flights. "Our teams have been working tirelessly to help as many of our customers as possible, in these unprecedented circumstances."