How to get rid of norton safe search. does not show up as extension

Hi. Not a tech guys but have tried this with many people in the past. I can’t get rid of Norton Safe search as the firefox browser on an imac. I’ve uninstalled all norton products, uninstalled and reinstalled firefox many times and it always comes back. When I go to the add-ons menu it does NOT show up on the list of extensions. I’ve uninstalled firefox and tried to strip the computer of any references to norton. I’ve had professional mac people help. …
Can firefox get rid of it for me?