If you are talking about Ongoing Harassment - the category where people in-game use other accounts, friends, or associates to contact a player that has them on Ignore - then that is done with a specific ticket.
You have to manually make that ticket and include the:
- Char name
- Server
- Chat channel
- Timestamp
- Nature of the contact.
- Reference numbers to past tickets about the issue (if any). You want the GMs to be able to see the related documentation.
You can actually write them down and submit them as a single ticket if you need to report multiple contacts in a short time. Just don’t wait too long or Blizzard does not have the logs.
Here is an article for you on Harassment, Ongoing Harassment, and what you can do.
Note: The forums do not have the same rules as in-game. People here are allowed to reply to you as much as they want, you are to put them on Ignore so you don’t see what they type. Eventually we will hopefully have Bnet account ignore so you don’t have to add each alt someone comes up with.