To answer your question. I could call you Dilbert, Dil but not the name someone called you as that is going too far.
The issue is they now know you get upset with it because they baited you to posting back. All you had to do was ignore it and don't reply. Now it's become an issue. I strongly suggest if they post again you Ignore it and do not post back. If it does get out of hand then by all means report it here and the team will deal with it.