There's nobody on my friends list with pc+mobile both

I tried send tickets, they linked me here.
I use battlenet on mac,pc,mobile, but there’s no friends on my list.
so I tried to add my friend’s battletag, and battlenet saids “you guys are already friends”

I tried everything on help like delete cache,reinstall …etc

what should I do?

I usually playing hearthstone, my friends can invite me but I can’t cuz there’s no list on my
friends list.
but friends can see me on there list.