How to relink unlinked groups?

I’ve have issue re-linking the groups that I unlinked from my file. When I try to link back the groups that i deleted it doesn’t show up in my 3d viewport. Please help !!!

Moved to Support Forum

Do you see them listed in Outliner window with Groups display instead of All Scenes?
It might take saving and loading blend file twice to get it going again because of the way link deleting works.