oferzel – How did you uninstall SupportAssist via the control panel?

Do you see any installation issues in the event viewer logs.

In Eventviewer - Look for eventsources = msiinstaller and ‘SupportAssistAgent’ then share respective error messages or event logs for review

Could also try to verify SA is deleted by confirming the following steps

• Uninstall via the control panel (if available), refresh if it’s not removing run the MS tool to uninstall.  (only run MS tool if not removing from control panel)
• MS TOOL https://support.microsoft.com/en-us/help/17588/fix-problems-that-block-programs-from-being-installed-or-removed
• Verify all the services are removed.  Uninstall should remove them but we should check anyway.  if any are not removed, then you can manually remove them by searching for CMD tool.  Right click and open as admin, run the following on any still listed or running. 
  • SC DELETE “Dell hardware Support”
  • SC DELETE SupportAssistAgent
  • SC DELETE DDVDataCollector
  • SC DELETE DDVRulesProcessor
  • SC DELETE DDVCollectorSvcApi
• Once the services are deleted
• Delete folder if listed "C:\ProgramData\PCDr\".
• Delete folder if listed "C:\ProgramData\SupportAssist".

• Delete folder if listed  “C:\Program Files\Dell\DellDataVault”

If they are all removed just download below exe, right click and run as admin

https://downloads.dell.com/serviceability/catalog/SupportAssistInstaller.exe

 If still not working would like to know what the event viewer is saying