If you want to claim a refund from KLM Airlines as you will not be able to travel anymore on the scheduled departure day then KLM provides you the customer service no to connect i.e. 1 (800) 618-0104. You can apply for a refund online by visiting the website where you need to click on the “Information” section after that scroll down and click on “Request a refund”.KLM Airlines follows a 24-hour policy, which states that flyers can cancel the ticket after 24 hours of buying the flight without any cancelation fee.