Parents aren't feeding you 15 years old?

ok, im 15 and my parents aren't feeding me. My mom and step-dad are in the navy, but she's always gone on the ship. And somehow im always getting stuck here with him, to be speific my step-dad is the one not feeding me, he feeds my brother(he's child) and my other sister (step-child). What i mean by feeding them is that he either fixes food for them or goes and buy food for them and leave me nothing. And when he buys food for an example groceries he buys little products like bread, bologne, burrito's, cereal, and bread. I have eatin bologne sandwichs for 3 weeks straight, and im sick of it. We have food in cabinet but its like uhm little sauces to make chicken(when he buys food, he hides it from me). Last year well last summer he did the exact thing. I don't know if my mom knows but he e-mails her like everything saying stuff that i do, but doesn't say anything about him. When i try to email my mom to ask for stuff, she just gets mad and says that's all you want why not email me saying how are you and etc. In my mind, it's like do you even know what your saying because everytime you call here is to ask for my step-dad, you don't ask me how im doing or anything. They expect me to clean but don't feed me. Did i mention that i don't say one word to my step-dad and he's constantly trying to pick on me by like everytime he walks past me he laughs or chuckless. I have nothing and barely have basketball. I asked her if i can play summer bball, she didn't respond (you need to $65 to play summer basketball). I found away to get in for free, so then i ask her if she can tell him to give me $20 to get something to eat for after my bball game, i still get no reply. So can anyone plz help me, what do i do. I can't get no job, I have no friends because they all have money and get to go places and everytime i'm with them its like ooo i cant cuz i dnt have any money. My hair is fallen out because i dnt know how to do it. Plz help me