1. If you want to keep the number port out to your carrier of choice,
2. If you just want to cancel, call 1-800-937-8997, and the #MagentaNinjas will cancel the line for you although they will be sad to let you go.
3. Contact T-Force via Twitter DM or Facebook Messenger Chat
4. Visit your nearby T-Mo store and present valid identification. They will be able to cancel the line in-store as well.
Manage your T-Mobile account