anyone got adivce?

so uh my sister has been calling me ungrateful because i have a phone and she doesnt, and she keeps blaming me for "breaking" her phone when her phone is from 2011. mind that i am grateful for my phone because one of my friends offered to give me theirs when they got a new one. she keeps begging me to be on it and when i tell her no, she just threatens me like to punch me or to tell our dad that ive been cutting myself (note ive been clean since september 11th 2020).

it honestly hurts since im the oldest child and shes the youngest, and like she can get away with anything while im over here just sneaking everything i do but then she finds out then threatens to snitch if i dont do something for her, like for example buy her coffee or candy or something.

can someone just give me some fucking advice here?