Hi , L. ...
Please don't be offended by this , but it does sound like your little girl is running the show. Hey , I , too , have a VERY strong-willed little girl so I can empathize ... we've had sleep problems off and on , too. It does NOT mean you are a failure as a mom ... it just means you made a mistake or two , something we ALL do.
That said , it sounds like you were on the right track with the reward chart. I'm surprised she lost interest in it.
Here , we do a marble jar with her name on it.
We buy one or two toys that are very appealing to her , and we tell her she has to earn 20 ( or however many ) marbles to get the toy. I think being able to SEE the prize is very effective for her , and it does work for the things we have used it for.
Also , from my Nanny 911 book , it says to put them to bed normally , then the first time they get up , put them back to bed with a short " It's bedtime ; goodnight" , and then the rest of the times , put them straight into bed , calmly and say nothing at all , with little or no eye contact.
There's also the Supernanny technique ...
she sits on the floor (with the child in their bed) , probably a foot or two away from the child's bed. After the kisses and stories and night-nights are done , and she sits on the floor , she turns so the child can see the side of her face ( no eye contact ) and does not speak to them at ALL. If they get out of bed , she puts them back calmly and says nothing , repeating until they are asleep.
Each night she repeats this , only each night , she moves about a foot or so more away , toward the door ... until eventually , she doesn't stay.
I hope some of this helps. Our daughter still sleeps in a crib , and come Christmas , she will be in a new toddler bed ... so I'll be trying the same things I suggested , lol.
Best of luck to you ... I know the sleep thing is such a taxing thing on the whole family.
~ A.