You can contact Tello's customer service team by filling out the form located at the Contact option of the Support menu tab on their website. You can also contact them by phone by calling 611 from your Tello phone, or 1 866-377-0294 from within the United States and +1 678 306-1436 from outside the country. Their customer service department is ready to help out 24 hours a day, 7 days a week.