How can I get my phone back, please help? ITS BEEN A MONTH?

I got my phone taken up because I begged my mom to go to my boyfriends house but she said so so i begged some more and she got mad and said no. So i didn't go.
When she came home from work she talked to me about how disrespectful I'm and how she doesn't want me going.
Then she took my phone and read all my messeges including the ones with my boyfriend and at one point he said "UGH I'm gonna kill someone" as an expression and she got super mad at that. Then I deleted everything off my phone from find my iPhone and she got even more mad. I wrote her a super long letter telling her i'm sorry and how ill change and i've apologized to her in person.
I'm in highschool and I really need my phone for extracurricular activities after school and in most of my classes. I've been struggling recently without my phone and I really need it but she doesn't seem to understand. Please help.
I'm generally a good kid. I make high A's. And i try not to make my mom mad but sh always ends up frustrated at me so we argue often. But this time she really blew up.

Maybe you can get another phone and just don't let your mom know you have one

Your mother needs to sell it and never give it back. You can't get another one sine you are a child and you can't own anything and have no right to have a phone and no right to stop your parents from taking what they want from you

You don't need a phone. No child does. Sine you refuse to obey your mothers rules, back talk and lie, there's no reason why should she ever give it back.