ADD and just not paying attention

I understand that certain disorders like ADD are frustrating for the individual suffering from them. Not with ADD in particular, but in general I understand from experience. But sometimes, it's a matter of sucking it up and doing something about it, and it honestly annoys me when people make no effort at all to do that.
My roommate is the particular one that annoys me right now. I mean she's nice and all. But she says she suffers from ADD. I've known people with ADD. when it's real light, they learn to actively discipline themselves and may never know they actually have it. When it's in the middle, they generally know, but again take extra steps to discipline themselves. When it's really severe, there are medications. Every time I talk to her, I have to repeat myself at least 5 times, and I'm actually not exaggerating is the sad part. And even after repeating myself at least 5 times, usually more, she still doesn't have it. And half the time, she starts saying what what I don't get it after the first 2 words. So that tells me that it's not ADD, she just doesn't listen. She does this to everyone yes, but it's annoying. And while I have extra patience for this kind of complication, I honestly don't think she has it, I think she just doesn't take the time to listen and pay attention.
Frankly, if it is that bad, you deal with it and take something and go to therapy or something to learn more about greater habits. But she refuses to take medication. So realistically, I have reason to be annoyed. It's one thing if you are trying to help yourself and it's taking time. Oh, and then she's literally going bankrupt and she says well there's nothing more I can do. But she works only part time, and then she's always out buying coffee at starbucks, buying her friends things, etc. So it's like yes, there is something you can do. I've tried to explain to her the concept of writing everything down, and it just doesn't stick.
And the other day, I specifically stopped her, told her to listen, because I was a little bit irked that for the umpteenth time, she called me to say well you want to go to coffee later, and then she never called back. She said oh well it was last minute and then I knew you wouldn't get there on time and then we'd be leaving. So I said well is there a reason that you couldn't text me when somebody texts you? And then she went into how she was so busy and she couldn't. It takes 2 seconds to text and say we're going. But she got into a rant about well I will just invite you next time. That was when I told her to stop and listen, because it's not about going to coffee. I was simply asking that she not call and ask me in advance, because every time it seems that she forgets later when it's time to actually go, so instead call me when they are actually going or if she forgets then it makes no difference. But she was so stuck in the idea that even after I told her to specifically listen, which you would think would suggest that somebody should listen for 2 seconds and actually concentrate if they have a hard time and actually try to process it, she literally did not process a single word of it. So I am a little bit annoyed right now.