seeking advice from australian law ?

my fiance and i have been told im never gonna see my little siblings ever again...for what reason???? because i had enough heart to allow my 17 yr old brother to move in and he managed to get his way on what he wanted brought into my home , after telling him to bring the bare minimal as its only a small apartment!! for a small $50 per week i allowed him to be apart of our household has him and his father kept having really BAD run ins to the point where they get in a scuffle..as you can imagine me being a sister of 7 children i thought the best thing for me to do is get him outta there..we laid rules down only a bed n two bedside tables are only to go in his room here and he agreed. our parents where fuming as they have just lost yet another income in to their home and his father tried every avenue to stop that ( control freak) ,so he gets drop off and left on our drive way with everything he owns and even tho he hasnt started to pay rent i allowed him to bring his stuff in until hes got some money behind him..over the weekend i recieved a lovely visit from my 14 yr old sister and i allowed her to call mum from my ph so mum new she was safe n not out somewhere she shouldnt be . she got off the ph and tells me fabes big fridge is coming in and there gonna drop it off soon..( not asking us but telling us ) so my fiance calls them and asks why hes bringing a fridge around as we already have a fridge and to note nicely two fridges is going to sky rocket our power bill and quiet frankly we werw concerned.. shortly after they arrived on our door pissed off and barged through the door.. they thru my brother in my face and told me to sort this sh*t out once and for all!!! i couldnt believe what was happening my brother wss disrespecting me and heating up an argument between us two with my mother putting her two cents in against me so my fiance took over and said look mate we laid rules down and you havent listened to not one of them...then my step dad comes in starts yelling into his face along with my brother and mother ready to punch on with him so i stand in the middle and asked them over 15 to just leave please..no one listened and i went to walk past my mothrr and she physically chuck me to the ground smashing my head against my recliners in the lounge.. my fiance went to help me up and twisted it that he was going to hit my mum ( which he wasnt ) all three raised up against my fiance again i kept asking them to leave and nothing.. then because they have no ammo on me they start saying to my fiance he doesnt know me and started bringing up all the bad things ive done in my life from 4/5 years ago ..and because my fiance wouldnt leave me abd said he already knew of all my life stories they turn around to me and said i will never be allowed to see my brothers or sisters again..they also left on that note. i helped raise those kids i have them over my house between two or three nights out of my week and i love it..i buy them there neccessities and i help them with there school work..i kno i am a good sister..i dont want them to take my siblings away as i havnt done anything wrong ?? im soo lost those kids are my everything and i pray for protection and love to guide them always