You need to grow up and be a big girl.
Are you 12? If you're a small child, then talk to your parents about it and ask them to take you to assertiveness classes. Take karate and chop the woman in two.
lol
If you're a teenager, than act like it! Teenagers are known to be moody and rude. That's your job! Take it seriously!!
If you're an adult, then holy cow, are you in for a really bad rest of your life. Because guess what honey bunch, life isn't like a tv sitcom. Everybody doesn't always get along.
Bottom line:
Grow a thick skin or find a very large rock you can live under for the rest of your life.
lol
Second, how did that woman send you a Facebook message?
I only get messages from friends and people I have invited.
So, clearly you love her drama, or you would not have given her permission to write to you.
It's called an "ignore" and a "delete" button.
I wouldn't blame this woman. She's just enjoying life, trying to push your buttons and succeeding.
Why? Because people like you are fun to mess with.
Me? I don't mess with people like you. I'm nice. But I scoff and roll my eyes at people who whine and cry about dumb stuff.
Get a back bone. Grow a thick skin and live your life.
Stop hiding and crawling behind every tree, quivering in fear of stupid people and the dumb things they say.
The new barn isn't yours. You board there. So, if the owner wants this woman there, then that's ok. If you see her again, simply take in a big breath and look her in the eye and say "hey, bee-och! Wassap?"
And give her the finger. Throw her words back in her face. She deserves it. Laugh her off! She's a joke!
Nobody can get under your skin without your permission.
Stop giving her permission.
After that, she'll leave you alone.
IF she doesn't, you can always resort to a karate chop to the nose.