Mazda of Salinas ca review: 2018 nissan sentra

I traded in my 2000 lexus which ran good as a down payment for a 2018 nissan sentra on feb 2022. Priced at 20000 was told it ran perfect it’s been 1 year and 4 months my transmission is complete failure. I’m left paying 509 a month till 2028 can’t get to work with a car, and now stuck unable to provide for me or my family. I contacted them they are very slow in returning response and when they respond never move forward to resolve my issues on what my options are