My problems with this story fall into two categories: narrative, and structure. Narrative first.

This is a long story, but whether it's too long, or not long enough, I can't say. In many ways it feel like an abridged version of a novel that hasn't been allowed to fully express itself. The story covers at least two generations, possibly more, depending on the nature of the evil presence involved. The kind of conflicts that swirl around such a malevolent force need time to ripen and reach their dramatic potential in a reasonable time interval. On the other hand, there's a lot of stuff that probably doesn't need to be there which artificially inflates the word count without delivering the punch that a tightly structured short story offers.

For instance, the first section spends 2249 words to tell us that Vic and her mother have just arrived in a new town, Vic doesn't like the house, doesn't like the move at all and that she an her mother miss their father, who died recently. There's nothing wrong with any of this information being conveyed to the reader, but all of it falls under the heading of set-up. Set-ups aren't stories and, save for the brief moment with her pet dog has a negative reaction to the basement window, your story hasn't gotten underway by the end of the section. If this was a Disney or Spielberg movie, your audience might be wiling to sit through all the normal, everyday stuff, secure in the knowledge that things are going to kick off eventually, but in a short story, you need to get down to cases and do so without waiting around.

The story proper actually begins in the following section, but you'd be forgiven for missing it, buried as it is in a quick bit of exposition amid a variety of other concerns. The section is titled "Maximus," the name of Vic's pet cat, but this is deceptive since Maximus doesn't have a lot to do. We also encounter Vic's new friend, and also learn, in passing, that we've jumped three months ahead from the end of the previous section. We don't actually meet this new friend; we simply get to read the text messages between them. She asks if anything weird is happening. We then get this paragraph:

Vic eyed the message and threw a wary glance at the brick wall at the far end of her room. Ever since moving in, Vic heard bumping and scraping coming from the other side of that brick border. She complained to her mom, but the disturbances came mainly at night. Since mom worked the graveyard shift at the call center, she never heard the strange noises.

That's the true beginning of your story, the point at which your reader will sit up, take notice, invest something of themselves and ask that most crucial of question: "What's gonna happen next?" The only problem is, you've merely referred to this moment in passing, in an after the fact generalization describing a class of activities, but avoiding the necessary task of actually offering us the activities themselves. We don’t want to know about “things” that have been happening. There’s no emotional impact in that type of narrative presentation. We want to experience one thing, in a specific time and place, as it happens, so that Vic’s experience can become our experience.

This is a failing of narrative technique. Note how you've given us a blow-by-blow, moment-to-moment accounting of the fairly mundane set of events in the opening section, but when you get to the truly crucial elements, they’re buried in abstract generalizations. Keep in mind that whenever you bring the camera and microphone in close and let us see and hear the events as they unfold in real-time, we're naturally going to consider such events important. Vic's encounter with the strange noises deserves a far more precise presentation than you've now offered. In this case, you've gotten the show vs. tell dichotomy exactly backwards. The opening material needs to be simply told. Vic's first encounter with the presence in the attic needs to be shown.

I would say that our introduction to Celia is also a failure of narrative; you describe her as Vic's best friend, but we have no sense of her. This type of scene can work in a movie—if it happens on screen, we take it at face value and assume it to be true—but in prose, the requirements, and approaches, are necessarily different. You can't rely on visuals and sounds to create the context. Everything has to be created with words and descriptions. Suffice it to say that describing Celia as Vic's best friend is something we'll have to take your word for, lacking any supporting evidence that we can actually experience.

But a deeper question regarding Celia is the role, or lack of it, that she plays in the story. She basically drops in on the story, tells Vic some important information, and then she dies. I don't suggest that Vic doesn't need a friend; I only point out that Celia is grossly under used. Her death scene tells us much about the evil presence, but isn’t it a waste of a good character to bring her onto the stage simply to kill her? As it is, the only thing she does is inform Vic of some historical information that, once again, constitute important material that is referred to, rather than actually shown. Come to think of it, why isn’t Vic the one to do the research. That way, the reader can tag along and involve themselves in the process.

There’s a mystery here, no doubt about it. I’m not quite sure what it is. Mom’s been presented as a fairly normal character throughout, until the last paragraph when she turns into… I don’t know what, only that there’s been no real preparation for the transition. There is a suggestion that she might be the adopted daughter, but this is not clarified, and the evil presence seems to simply exist for the purpose of providing evil. I agree that evil doesn’t need to be explained; it’s not a psychological manifestation, after all. But there are gaping holes in the tapestry of your plot that probably could stand to be filled in a little better.

This has the elements of a good horror tale. Work on tightening your structure. Characters tend to run through a variety of responses when confronted with the supernatural, before giving in and accepting that, yes, this is a monster. Vic should have a period of denial, avoidance, negotiate and rationalization before getting hit with irrevocable evidence that she’s in an other-worldly situation.