Feedback and mobile app buttons

I have used PowerShell to set the tenant level setting for showing the feedback button to false, e.g. 

set-spotenant -UserVoiceForFeedbackEnabled $false

...but the feedback button still shows. Also how do we get rid of the "Get mobile app" button. Neither of these are appropriate in a large enterprise Office 365 and cause confusion for users resulting in support calls.

How can we turn these off?