I'm so sorry, they are emotionally abusive and treating you horribly! It's totally unacceptable. This is 100% their f*ck up and not yours. You are worthy of love, care and an awesome birthday.

Some practical solutions: Do you have any friends whose parents you can talk to about all this (not just this incident, buy in general how they treat you)? Can you stay at a friend's house for a while? Can you talk to any relatives or teachers whom you trust? You might even want to consider getting in touch with social services.

I'd also recommend getting a part-time job if you can, and each pay check is one step closer to freedom!

Also, happy birthday! If I knew you irl I'd give you cake, presents and a big hug❤️ you deserve all the best. Don't let anyone tell you otherwise! Stay strong, and know that reddit has your back!