Installation failed - installer corrupted?

I have just bought Norton 360 premier but the installation keeps failing saying 'your installer is either corrupted or missing important resources'. It says to contact support but support is closed down due to Covid - 19 apparently. I'm getting really frustrated. I have a MacBook Air and I'm not very tech savvy. Please can anyone help?

I have asked this thread be moved to the Mac board for better exposure to Mac users.