Hi there,
All you can do it try to go to her farm and catch her avatar, then click on it and choose to "ignore" or "Report abuse", which will send in a report to the developer team. Unfortunately these people may have numerous accounts and regularly change their avatar name. I have myself seen these and have managed to block some of them and no longer see them.
i have a question for u..its been a long time since ive played farmtown. my land has snow on it and want to change it back to grass. where do i go to do that. ive looked in path/grounds and farm decorations?