Problem in removing event listener

import { el, css } from './utilities.js';

export default class MaketempDiv {
    constructor(x, y) {
        this.father = x;
        this.onstart();
        this.y = y;
    }
    exportFn(y = this.y) {
        document.removeEventListener('mousemove', this.dragfn);
        document.removeEventListener('mouseup', this.exportFn);

        this.exportedDiv = this.temp;
        this.temp.parentElement.removeChild(this.temp);
        this.temp = null;
    }
    dragfn = (e) => {
        css(this.temp, {
            width: `${e.clientX - this.initPos[0]}px`,
            height: `${e.clientY - this.initPos[1]}px`
        });
    }
    onstart(y) {
        this.father.addEventListener('mousedown', (e) => {
            this.temp = el('div', this.father, ['class', 'tempo']);
            this.initPos = [e.clientX, e.clientY];
            css(this.temp, {
                left: `${this.initPos[0] - document.querySelector('.tskbr').clientWidth}px`,
                top: `${this.initPos[1] + this.father.parentElement.scrollTop}px`
            });

            document.addEventListener('mousemove', this.dragfn);
            document.addEventListener('mouseup', this.exportFn);
        }, false);
    }
}

document.onmousemouse = ....