red headed stepchild

backround: I live with my dad and step mom. she raised me from age 3. shes my mom always have been. getting into why I'm mad. I have a 11 year old sister who's birthday was today. she already has a iPod 5 from 2015. it's actually her 2nd one because she lost her last one and it was missing for less then a week and my step mom ran out and bought her a new one. also she has a iPad, DSi, 3DS and. 3DS+. she got a new iPod for her birthday today. when I've had a tracphone that has a button keyboard for 2 years because I messed up and didn't even get in legal trouble my 10th grade year. ever since then I've been treated like a piece of shit like I'm going to screw up my families life by breathing to loud. my parents just yell at me about how I ducked up my life so badly. I didn't get charged I had to go to a class for sexting. 1 class. no fines no record. nothing. after I got in trouble 2 years ago I went away for a summer and worked at a church camp to get away. and now I lifeguard and I also was a CNA at a nursing home last summer. I teach children how to swim every week. I know where I'm going to college but when I asked my step mom for help in how to apply for different things she forgets I ask then weeks later gets mad I don't have my shit together already. I had a iPhone 6 2 years ago. I got it after I had a galaxy s4 that broke. my dad offered to buy it for me. I didn't ask. I was fine with using a used iPhone 5. but now he just hitched at me that I'm ungrateful and I had screwed up my life forever by being stupid and sexting a kid 2 YEARS AGO. I've apologized. over and over again. I work. I don't ask for much. I asked for the past year if I could ever have my iPhone 6 back or even iPhone 5 back even just my iPod. and I get told I'm ungrateful and have no right to get it back because I messed up so bad. my dad bought me a 60 dollar tablet on eBay 2 years ago that I've been grounded off of from my step mom because " I'm ungrateful and rock everything up" I am grateful. my life would be hell of a lot different if it wasn't for my dad getting custody of me. but he tells me I'm ungrate for him and my step mom raising me? what am I suppose to do instead? be raised by the neighbors? that's what parents do, is raise their children and aide them and help them. but no I can't ever have a smart phone because my family might get murdered in their sleep because I'm such a screw up. I have good grades take several college classes in school. I buy my own clothes makeup and I have had a steady relationship for the first time ever. but I'm still a screw up and don't deserve anything because I made a mistake 2 years ago that I learned from. and I repeat NEVER WENT ON MY RECORD DIDNT HAVE ANY FINES NOTHING BUT A 2 HOUR CLASS I HAD TO SIT THROUGH. But I don't deserve anything. but my sister and brother get anything they want. I'm 18 offered to pay my own phone bill and everything but still not allowed. sorry I'm such a screw up, but I'm trying my best but I never do anything right.