HELP ME!!!! what do i do?? please!!!!?

my parents treat me like ****. i am 11 and a girl. my parents and my brother hates each other btw. i saved my money (from my 19 yr old brother) and bought myself an expensive camera and laptop. my dad accidently on purposely lost my camera and bought me a cheap one that sucks. and disconnected the wi-fi so only their mac is working. my brother bought me an iphone 3g for my birthday and my parents gave me a phone plan but soon they started yelling at me because they said i am on the phone too long (trust me im not). i asked them for a sleepover with my best friend but they said no and started yelling at me because they said "i cant take care of myself" when i literally have to buy every single thing myself. and they just took my SIM card away so i only can use by brother robins phone. i am on this band with my bro and his friends and my parents know how much this means to us because music is our priority. when they know they cant afford not having me at practice because i am a very gifted musician (not to brag) and i alternate between piano/drums/bass/electric guitar and i also play flute and alto saxophone they dont let me come to practice because they think its useless and its wasting my time. when i tried to tell them how important it is my mom just grabbed me and started hitting me. i dont want to give them any trouble by calling the police or something but this is not the 1st time and it hurts bad. they did other stuff too me too. i even thought about running away but i will miss my brother because he is the best person ever and my role model and i will also miss my two dogs. i dont know what to do please help me!!!!!! i cant live like this much longer because i cant stand it. thanks in advance.