Family issues e.g. spoilt sister.?

I have troubles in my family as with 3 sisters and two being segregated against singled out if you like. My youngest sister is 27 and has had everything given to her from very young. She just needs to ask and act down and depressed like a spoilt brat and 9 times out of 10 she gets it. My oldest big sister lives in Edinburgh and doesn’t take much to do with my family i can see why now. Me i am like the spawn of Satan to my step dad he is not in any means my real dad but as for my youngest sister she is the opposite, Miss Perfect good two shoes can do no wrong. drives me nuts as i still see and talk to my mum am not as close to her as i was years back but that’s because of the way i was treated she told me she was trying to Hate me because of the man she apparently loves so much he is more like a parasite than won’t die. My mum’s makes excuses for his behaviour several times and uses her illnesses as a way of getting out of being asked questioned about the way her man is with us two also her grandson my son who is now 18. I am wanting to learn to Drive and my sister the spoilt one got put through her driving most paid for and not paid back plus 2 £1000 university courses that she never bothered to learn never paid back has had 3 holidays paid for not paid back helped out whenever she need petrol or car parts etc. and has had £3000 for help with buying stuff for her new house also helped out to buy Christmas presses for her boyfriend and pals and on-going number of things. Me and my other sister get second hand stuff rejects and helped out now and again but made to feel guilty or extremely grateful for it. Sickens and saddens me as my mother who always said she would never take a man over her daughters ever under no circumstances or favouritism with them has done exactly that, in every sense of the word. She doesn’t seem to have the love as much for my older sister who lives in Edinburgh complains about her all the time. Never visits or calls her. I haven’t spoken a sentence to my step dad for years he hasn’t spoke to me and ignores my older sister when she visits makes us both feel unwelcome. I feel he took over as soon as he moved in over 12 years ago. I think he has manipulated my mother’s thought to such a degree that she can’t and won’t think for herself. I would love to know if anyone else has the same or similar upsets as I do as I feel as if am the only one...