DD12 is becoming completely unbearable. Swears at us, lies, doesn’t do what she’s told is spiteful and has stolen money from my OH and I and my 10 yo DS. She is very aggressive to us most days. Started her period around a year ago and it’s definitely worse on her monthlies, Which we make allowances for. A lot of the bad behaviour is centred around her phone. We have tried everything, Ignoring her , supporting her, talking, not talking, taking phone away, limiting screen time, more family time, less family time, Space and time on her own etc. She was a very well behaved toddler and child, always worked hard at school ( still does and gets good grades) but for the last year she has changed into someone I just don’t recognise. Tonight we let her have an hour and half on her own in the house as she enjoys her independence, she was supposed to do homework and have a shower. Despite promising She didn’t do any of it and when I took her phone off her when we got home, to get her focused, she gave me an absolute tirade of abuse and aggression. DS is distraught. DH and I at wits end.. we think it’s time to seek help. This is literally ruining our lives. I need some advice from you wise people! Please help x