Termination fee

Dish is trying to charge me early termination fee of 400.00. I have returned their equipment. I called in September to get third TV hooked up, tech came out hooked up joey. Had me sign his tablet he said it was to verify he came to hook up and that every worked before he left. Now I'm being told that I signed a contract stating I signed up for another 2 years. No I did not. Called CS several times, no one will even negotiate the fee.