Sold A Car To A Lady And Now She Is Threatening Me With Her Law Inforcement Relatives

I sold my 2002 ford mustang to a women in WV . I listed it on FB marketplace and I showed the dash which had an engine check light on . She messages me and asks me if the car had any problems and l told her what was wrong with it according to how my mechanic had told me. So she asked me to bring the car to her so she can see it cause she wanted a car for her daughter .so l took the car to her yesterday morning she had a guy with her and he just checked the hood and she peeped inside the car (didn’t even open the door or drive it) . And the guy told her to but it and she said l should get the tittle and bring the car back cause l had left it at home so l did just that brought the car and tittle back . She cash apped me the money. I sign up over the tittle and give her the keys to the car, l left . About an hour later she texts me telling me that the key won’t turn over . I messaged her back and told her that i wwas impossible that the car won’t turn over and l tried to help her. Then we agreed l was gonna go and check it last night after my shift but l messaged her cause l couldn’t go. I woke up this morning to her threatening me saying that her sister and brother inlaw are cops and they were gonna make sure she gets her car back . So me now being curious about the situation l went back to her work place to look at the car and the key is turning over but nothing is coming on the car not even the lights on the dash. I think they did something cause l have proof that the car was in perfect running condition despite the problems it had . So l need advice on what to do cause lm not from the US and l can’t afford any of this drama coming my way rn.