What do you mean that it's not working? that it's not getting you flat enough?
I also use the 997 and it doesn't get me very flat, but flat enough that I'm okay with it. Also, I have found out (from people telling me and now from experience) that wearing a binder for a long period (not consecutive) of time making getting me flatter easier. it sort of makes my boobs squishier and therefore easier to bind.
Since you have the 997, have you tried folding it up to give you twice the layering? that might be better than ace bandages.
Although I do admit that when I first got my 997, I still preferred ace bandages because they got me flatter.
You can could try exploring with wearing a sports bra under your binder and things like that.
I think everyone's body's are different, no matter how similar they look. So even someone bigger than you could have an easier time with the same binder for some reason. I think you just got to explore and find what works for you.
Also, when I got my first binder from underworks, it said that I needed a large, but that was WAY too big, I got a small, and it worked much better.
So that's a big huge size difference there. Of course, now my binder is stretching out so I find it's not binding as well.