How do i block & remove someone on Facebook when their name is in black & i cant click on their page?

[asha]

Years ago I was friends with a certain individual on Facebook then it had appeared as tho they had deleted their account - their name wasnt showing up in my friends list, their tagged name dissapeared in a photo, and their comments were suddenly removed so i assumed they had deleted or deactivated their account. Years later they private messaged me something about something they had seen on my page (the status was not set to public only friends) so this led me to believe they were still in my friends list, although their name showed up in black and i was unable to click on their name/page to delete and remove them and i couldnt reply to the message. I have alerted facebook but they have not gotten back to me yet. I am annoyed and want this person gone. I typed in their name on another account and their name showed up and i was able to click on their page. but with my account i want to use, i cant seem to get rid of them, although they can still look on my page..? how does this work? any suggestions with how to get them blocked and removed?
cheers
the first answerer is not reading what im saying!!!! i CANNOT click on their name in my facebook, they dont show up in my friends list because they have made their privacy settings so high towards me.