Office 365 E1, Business Premium and Essentials licenses only provide Skype for Business Basic client, which does not include Voicemail or Call-Forwarding features.
The following instructions will guide you through the uninstall of Skype for Business Basic from O365 Click-to-Run package and install of Skype for Business Full, which includes Voicemail and Call-Forwarding features (Please note: Skype for Business Basic must be removed before the install of Skype for Business)
Uninstall Skype for Business Basic
1) Download the Office 2016 deployment tool Here
2) Once downloaded, run the application to extract the files which will include setup.exe and some configuration files.
3) Download either configuration32.xml or configuration64.xml (32 or 64 bit Office) attached at the bottom of this article and move it to the same location as the extracted setup.exe.
4) Open Command Prompt as Administrator and change the directory to where setup.exe is located (cd command).
5) Run setup.exe /configure configuration32.xml (or setup.exe /configure configuration64.xml) which will kick off the uninstall of Skype for Business Basic.
Install Skype for Business Full
1) Download Lync 2013 from here
2) Install the MSI once downloaded.
3) Go to Windows Update page and select Advanced Options, ensure that Give me updates for other Microsoft Products when I update Windows is selected.
4) Check for Windows updates and install these to update Lync 2013 to Skype for Business 2015.