To complain to Expedia, start by contacting their customer service through the official phone number or live chat available on their website or mobile app. Make sure to have your itinerary number, travel dates, and any relevant documents ready to help the agent understand your issue. Clearly explain the problem, whether it’s related to a flight, hotel booking, refund, or cancellation. If the response you receive is not satisfactory, you can escalate the complaint by requesting to speak with a supervisor or by submitting a formal complaint through the feedback or contact us section of the Expedia website. Include all important details, such as booking information, dates, and screenshots if available. If your issue remains unresolved, consider sending a written complaint to their corporate office. You can also use social media platforms like Twitter or Facebook to publicly address your concern, as companies often respond quickly to visible complaints. Additionally, if your case involves financial disputes or refund delays, you may contact your credit card company to dispute the charge. Make sure to document all communication with Expedia, including names, dates, and reference numbers, to support your complaint. Being polite but persistent often helps achieve a quicker and more favorable resolution.