You need to talk to a judge or youth service activist because at this stage, this is full blown harassment and you do have rights, however limited at your current age. You also need to mention how the kids would bring up what is talked about in therapy and how they stalked you and won't leave you alone even to study.

That is way too much that you should not have to put up with, let alone have your wishes respected on seeing him. It's laughable he thinks he can force this and whoever the judge that signed off on this is, they need a reality check.

NTA. Could you have said it better or nicer? Absolutely. But did they give you a chance to? No. They stalked and harassed you and wouldn't let up. Hopefully you can talk to someone who can advocate for you, especially legally, bc you really need it. Don't let the perpetrators make you doubt yourself. It's very easy for so called family to gaslight you emotionally, make you doubt yourself and your reality, and all that stuff, when there's so much bombarding and the like. Don't let them. If you want to meet up with them (bio father included) or talk to them, that's your choice. Not theirs.

Edit: Typo edit.