Hello,
is the product you are trying to uninstall Avast Antivirus for Mac? If the AV is version 12 or older, you can try to run uninstaller from terminal via:
open /Library/Application\ Support/Avast/components/uninstall/com.avast.uninstall.app
or directly the script
sudo /Library/Application\ Support/Avast/hub/uninstall.sh
Kind regards,
Ondrej Kolacek