Princess Alison if you follow the first two guidelines from the user agreement about problems with other users it should solve it.

Put that user on your Enemy list
Hide and ignore the other users post. Instead of starting a "flame war" with the user, just ignore them. It takes a bigger person to ignore than try to sink to their level.

Posting about a specific problem here isn't really a good idea because if they read your posts they may feel the need to respond, and before you know it you're in a public argument which would get both of you hidden!