Check Engine Light On problems of the 1998 Mazda Millenia

I fully purchased my car on 02/28/2019 with "auto landmark". That same day I paid a $200-300 service fee for registeration and title, I paid full car tax on the car. I call in regards to my car and if the mechanic it's not calling out, he's on vacation. It's been over a month and still no results. They just need to remove the check engine light for emission which I paid in full for. . I have court because the paper work I have are photo copy not original officers couldn't take it nor the dmv. I lost my job because they kept my car for so long and still refuse to update me on the car. Please help me get car back or have them finish there jobs. They're definitely toying with me and I don't know what I can do about it. I need the car with plates and registered and they refuse to give me a refund for me to do it myself. So I'm left with them finishing the job. Please help.