Power of Attorney dispute can I contest.

[Ellen1]

My sister I assume has power of attorney of our family home. She has been caring for my sick mother claiming careers benefits. I also went to care for my mum after work hours till the next mornings, leaving my partner & children at home some nights taking my eldest daughter with me to help mum. I was never notified of any goings on with POA or my mums will. A week ago my sister ordered me to remove my belongings from our family home as she moved my mother in with her. Her daughter percussively swore several times at me along side have her husband with her whilst I packed up my bedroom. My sister asked me to make a list of things I wanted of which most she said I could not have. I have 3 children two sons who carry my family name & me being the 2nd surviving sibling of 3. My mum is deteriorating slowly from I’ll health & my sister has taken over all her estate. Do I have any say over the POA and what can I do. They chained the garage door so I could not remove anything from which my father inherited me.Her daughter stays at the premises watching me remove anything I wanted. It became very heated before I left as my sisters husband came forward with his friends I assume to collect items they wanted. Very confused as my dad past and most things left to me were sold by my sister in the interest of my mother? ( sick & incapable of doing these things). Can I contest the power of attorney as my mum is still alive.