Prematurely ageing due to 3 year old

We are at our wits end we have a 3 year old girl who will not listen.We tell her something is dangerous and it will hurt her not to touch/do it and she goes on doing it regardless, today was the oven she knows it's dangerous but sneaked over to it anyway only I seen her as I turned her hand would have been burned. Tell her to go in the corner as a punishment NO tantrum, ask her to eat no tantrum.Every meal time is a battle, we have to watch her 24/7 for fear of her hurting herself due to doing something she has had explained to her that it's dangerous. She was ripping wall paper fair enough she is 3 then I realised there was no paper on the floor she was eating it.We tried ignoring the bad she escalated until we had no choice but to step in, we praised the good she did a bad thing straight after the praise. 2 hours screaming every bed time, kicking the walls, bouncing on the bed, shouting that we are hurting her when no one is in the room. Pretending she has fallen we call to make sure she is alright silence until we enter to investigate.We tried swatting her hands away with a sharp slap to the back of the hands, she laughed at us, she looks you straight in the eye when we tell her no and does it anyway. Talks from she wakes till she sleeps, wakes up very early and sings top of her voice to wake the entire house.Me and my wife are beyond tired, any ideas for a family that has tried everything and nothing worked. via /r/Parenting http://ift.tt/2fmqRYF