What help can I get with my mum

I have a carer support worker who I try in vain to contact. I was to do a Carers support plan but no one ever gets back to me from the Carers centre.
My mu is 92 and has dementia she hits me a lot and it’s getting sore I’m her only carer and I do have Power of Attorney, but here the problem is no one will declare her not to have Capacity she in my view does not have Capacity everyone says where do they get that from. She needs bathing shown how to do most things for instance how do you make a cup of tea what do you do with this a tea bag.
If she were to go out she would have no idea if where she is.
She has crippling anxiety and she gets violent. Her Social Worker cannot do anything her GP will not do anything. I get to bed at 2.30 up at 6.30am I’m tired and stressed and get no help because she says no or sends them away. Mental Health have discharged her because she asked to leave.
I have no help and no support and I’m lost.
Can anyone advise me please.

Use your phone to record mum’s behaviour and next time she gets aggressive dial 999 and hide in your room. This is physical abuse which cannot be allowed to continue.