I have found the solution! I also have been trying to use free my apps and the limit ad tracking is locked on green. so I looked at restrictions and it wasn't restricted. After a week I thought "what if my wi-fi forces it on?" so I turned off my wifi, and it let me turn limit ad tracking off, but then when I turned the wifi on again, it turned it back on. so what I did was this.
1. Turn off wifi 2. go to limit ad tracking and turn it off 3. go to restrictions and for advertising select don't allow changes.
4. turn wifi back on and if you look at limit ad tracking it shows a loading thing where the switch is.
even though its a loading thing, free my apps started working!
it works because I made it so the wifi can't change it because I did don't allow changes