Does it ever end?? This constant battle between Adult Skids and Step parents?

As predicted months ago, SD25 deleted me off FB today. A silent way to say she's mad at me or she's "done" with me....or maybe she's declared war. I am sure this is being done in honor of BM- who is scheduled to move back into the state in the next few months. I am sure this is her way of declaring war in honor of her sister, SD23, who we finally booted out the door 3 weeks ago. This is her way of telling me she does not approve of ME in general. The funny thing is, me and SD25 have not been having issues that I knew about. She comes over our house, uses our internet to do her homework, uses My printer (and paper and ink) whenever she feels like it. We babysit 1 year old Grand-dtr every Saturday when she goes to class. WE have not had any bad words between us. However, she has been spouting off to my BF- details I am not privy to. But I get bits and pieces of the poison she is spreading. BF doesn't take any of it seriously and tells me to do the same. But how can I just sit back and pretend nothing is going on? How can I let her come over here- and purposely ignore me- while she is free to use things that I Pay for- yet she doesn't like me?? I am really torn about what to do and how to react. If I do the things I WANT to do, I might be seen as the EVIL STEPMONSTER :jawdrop: she is making me out to be. On the other hand, if I ignore it and pretend I am not affected by any of it- I feel that I am just letting them walk all over me.

So the EVIL STEPMONSTER- thinks I should lay down some rules and put up some Walls. IF SD25 doesn't want a relationship with me- that is HER CHOICE. But she can't come over and use our internet(which I PAY for) and my printer and ink/paper. She can't use the Sprint WIFI box that costs $60/month- which me and her dad split the cost of even though I NEVER use it.( I bought it last year when I was traveling alot and needed wifi in my DC apartment.) Now BF and SD are the ones who share it- but I AM STILL PAYING for it.
Why should she continue to benefit from things that I am paying for when she has declared her hate/anger/resentment- or whatever this might be? She has been trying to get her dad the EX back together and I think this is a delusional idea she won't let go of. SO I think she is just trying to push my buttons and have some sort of silent War against me. So far only SD21 is the only one who at least Pretends to have any respect towards me.

The Decent human being who wants to take the HIGH road in me......is debating on what to do about Xmas. How can I buy gifts for just SD21 who is still being nice and respectable? If I don't buy "something" for the other 2- and the grand-daughter- this will just validate their idea that I am a monster. But if I do buy them something- and I'm not even sure I am going to- I think they will be the evil step- children who think they are getting one over on me???

I have not declared war- SD25 is responsible for that. Me and SD23 were already entangled in a battle of our own- one I thought would get better over time. Now I have SD25 and BM throwing gasoline on this fire- making it much harder to extinguish.

How can Step-parents find balance when Adult skids are bound and determined to make life difficult??? I feel like these brats are bringing out the Stepmonster in me- like a Dr. Jekyl/Mr Hyde. This is not the real me- but I have every right to defend myself and my sanity even if that means Showing them What a Reals STEPMONSTER I can be }:)

BBGF