Suspend a line steps: https://www.t-mobile.com/support/account/suspend-or-restore-your-line

We have an option here to suspend the line, to block from usage. And once you need it again, we can definitely restore the line as well. Would you like to proceed?

For the T-Mobile app:

1. From the T-Mobile app home screen (learn how to install the app).
2. Select the Account tab.
3. Select the line you need to update.
4. Choose either Report lost or stolen or Suspend a line temporarily, depending on the type of suspension you need.
5. Follow the on-screen steps to suspend or restore your line.