Stop doing d4 slice, only cancel into slice on gapless strings for the most part (b31, f21, etc...). Instead you gotta play a really strong neutral game with her until you force her to take big risks. Try and stay just outside her b1 range and use standing 2's and f4's to whiff punish since they're faster than f2. I primarily use f2 as a backdash punish or pressure string over a whiff punish in this matchup. Only zone fullscreen and don't just zone, try and input DF motions and moving back and forth to try and bait out tele or a reaction from Mil. Once you get a sai throw you can jump air ball to blow it up as long as you do it fast enough, same with low sai. Tele kick just bait, crouch block, and punish with d2 to avoid eating air sai follow up. If you read the follow up you could just wait and let it whiff, and 112 punish OR if ya wanna use the bar, crouch block the tele kick then immediately ex buff and go straight into a f212 combo. Mileena is a sitting duck in that situation if you time it right. Anyway I hope this helps some, I'm still trying to break down the matchup more myself. Just be extremely patient in this matchup and you'll do real work to mileena.