Need advice please

A little background...i was a young mom (had my first at 18) had 2 daughters with the same guy, we got married and then divorced. The divorce was dirty and he ended up getting custody, the girls have lived with his parents since. Their parenting style is not anything close to mine. They do not discipline and give my girls everything they could want and then some. My girls are now 11 and 9, I always make sure they know how much I love them and would give anything for them to live with me but his parents and of course him control the situation and that has not happened yet. My concern is for my 11 year old. She was diagnosed with RAD (reactive attachment disorder) at the age of 7, she has always suffered with anger issues and acting out physically toward her care takers...well I thought we had it under control for the past 3 years anyway, her grandparents and father lack big time in communicating with me and always have. Here about 2 months ago she started her period so of course she more moody than she's ever been. She has started cussing, hitting,saying very very hurtful things and threatening to run away. With all of this going on she still doesn't get disciplined, gets whatever she wants and never gets in trouble at all. As a parent who has a hard time getting any of them to listen to me I don't know what to do....im scared that if nothing is done she will do something very stupid and end up getting in trouble with law enforcement. I don't know what to do as i don't have custodial rights....any suggestions would be greatly appreciated.