I want my iPhone back?

[MANU]

OK.. So my dad took my iPhone away three months back because I got into trouble. I have been making better decisions and I have not been doing anything bad. Now, when I ask him for my iPhone back, he says that "I don't want to pay for the data plan... it's too expensive" when my sister, who is in college has an iPhone. I say "Well. Mahita (my sister) has one... It's not fair. I've been good and I've been doing amazingly in school." He says that my sister is in college and she can have one, whereas I can't. He said that she is older and that she has a job and stuff like that. SHE DOESN'T PAY FOR THE BILL! SHE DOESN'T EVEN HAVE A REAL JOB! SHE DOESN'T GET PAID! All she does are the same things that I do! Use Facebook, Twitter, Instagram, SnapChat and other things plus calling and texting. My dad says that he'll give me the most basic phone so he doesn't have to pay for the data plan. I feel that it is completely unfair that this is going to happen. It's not fair at all for me at all. He bought the phones for both me and my sister and he says that I only need a phone to communicate, not use anything like that. My sister does the same EXACT things as me on her's, yet she gets to keep her's, when she doesn't make any payments on it whatsoever? This is complete bullshit in my situation and completely unfair. Please give me some advice on going about this; I want my iPhone back.