Phone Number of T-Mobile Customer Service is 1 (800) 866-2453. Get full detail information about the various services that T-Mobile provides. Find the correct customer service phone number as per the services you require from the listed below to get help. Get connected with T-Mobile customer service to know about new customer subscription, help for a prepaid customer, track online orders, check service end date, assistance for business accounts. You can also get connected with the T-Mobile customer care and get help via Twitter by using @TMobileHelp who are available 24/7