How do you tell a person begging you to do something that you don't want to do if they call you everything under the sun?

I'm a teacher and I have been begging my principal for the last 3 years not to give me kindergarten. They insist on giving me the age group even when I tell them I have wanted to teach 4th grade for 7 years. They told me I don't know what I want.<br><br>I then told them I don't want to have children ever. I told them a million times throughout the 7 years I've been teaching. I even told students, students' parents, parents of other kids I teach, and even the headmistress.<br><br>A month ago, the headmistress called me into her office along with the principal. She told me that she wanted an employee to be the model who goes on TV to show how to make proper babies. She told me it would be awesome if the school model for "proper child rearing" was me since I've been with the school for so long. I was flabbergasted at the utter gall that they had. I repeated that I don't want kids. They told me that maybe I just need to meet the right man. I was flabbergasted. I told them no, but they told me it was a fantastic offer and that they would be really happy if I "decided to change my mind and accept the offer." They made me sit there and eventually I had to leave after saying "no" 20 times and putting down the paper they gave me.<br><br>It's been a month now, but this week I saw the headmistress and principal talking in the teacher's lounge. I walked by and the principal told me that one of our coworkers "did the right thing and decided to become the school's model for raising children." I walked away with them talking behind my back saying "now SHE won't lead the students astray." I felt so damn shit.<br><br>Next week I told the headmistress and principal that I don't want kids. I don't want to talk about it. I don't want to change my mind. I don't want to become the school model for raising children. I don't want to be badgered. I told them it's my decision and my decision only. The principal rolled her eyes and walked out, saying "you don't know what you want!" The headmistress told me that it's sad that I'm "too scared to grow up."<br><br>It's my decision. I don't want to be badgered anymore. I don't want people to think I'm immature or scared to grow up. I don't want to be treated like I don't know what I want. I don't want to be told I'm leading students astray by not wanting kids. What do I do? How can I make them see I know what I want?<br><br>What do I say to them? I have begged them to listen, I have yelled at them to listen, but they won't listen. They insist I don't know what I want! I've told them I'm childfree since my first year!<br><br>I want them to leave me alone, but they won't. What would you do? What would you say?<br><br>TL;DR: I've told my principal and headmistress I don't want kids a million times but they won't listen and treat me poorly. What can I do?<br><br>Edit: I live in South Korea. I'm not sure what laws there are here about this stuff. I just want to teach and live. I'm begging them to listen to me. I told them I would transfer schools next year if they keep giving me kindergarten. They just laughed and told me that I don't know what's good for me.<br><br>Edit: Thank you for the comments and advice. I really appreciate it. I am seriously considering speaking to a union person and/or lawyer.