Updating Norton Anti-virus for mac

Someone please help - I'm tearing my hair out !!!

I've been running  - Antivirus for MAC on two machines  - for years 

I bought it originally for more than one machine and keep updating the subscription without any problem 

BUT

This year it only updated for one machine and there is no way to buy an additional product code

as it's not showing the "product tab" in my account...

Is there anyway around it or am I stuck with buying another update !!!:smileysad: