Can a blacklisted IPhone be traded in?

Recently I went into care (i am 17) and my mother blacklisted the phone which i’ve been send her money to pay for under her contract. I barely managed to pack any of my clothes which I would’ve sold by now and have no way of letting the people who care about me know i’m safe. I was going to try trade in my IPhone 13 pro max (blacklisted) but i’m scared they’ll think it’s stolen and take it away from me. I need it as it’s my only form of communication when i’m connected to Wi-Fi but if I can trade it in and get a new for and keep all the stuff on my Icloud can someone please let me know. I’ve already lost tons of pictures and stuff and since she blacklisted my SIM as well i cannot even access or verify things like my bank account etc.

P.S

if i show proof that the only apple ID ever registered to this phone belongs to me will the help. I don’t even mind if they unblacklist my current and let me keep it I just need my phone and my stuff back x