I have a seven year old daughter, who has horrific tantrums, whenever she is asked to do something, she has now began to lie and insults me, Recently she hit me and is constantly cheeky and lacks all respect for adults. I separated from her father three years ago and he took this very badly, he is a violent man, and talks very badly about me to my daughter, I think this is emotionally disturbing her and takes all her aggression out on me, Any advice??