Go to the Sophos Mobile Control Self-Service Portal and log in with your Active Directory credentials.
Click on the device you want to uninstall Sophos Mobile Control from. Click Select an action, then click Decommission.
After decommissioning the device, click Select an action again, then click Delete.
On the device you just deleted, uninstall the Sophos Mobile Control app. Hold down the app on your screen with your finger until you see an X at the top left corner of the app.
Click on the X and then click Delete. This will delete all the data with Sophos Mobile Control.