Support Assist won't update and can't be uninstall

Hi, I'm having some issues with Support Assist, it won't update! I'm stuck on 3.10.4 version of it. And it won't let itself update! And I tried to uninstall it from my computer but it refuses to do so, it says I'm missing a file, called "Supportassistx64-3. 10.4. 18.msi" And I need it in order to uninstall it. So... I'm basically stuck! And I don't know what to do, and can't find a topic of someone going through the same issue.

Does anyone have a solution for me? Please.