Starting a call from MacBook - Your iPhone needs to use the same iCloud and Facetime
Solution 1:
To see devices attached to an account:
- Sign into the Apple iCloud via a browser as the account you want to check
- Drop down the arrow next to your name (top right)
- Choose 'Settings'
The screen will then show you devices that are attached to that account.
The device MUST be running iOS 8, macOS Yosemite, or watchOS 1 or above (not an issue in your case).