I sold some computer parts to some guy . We met up at my apartment lobby. Showed him a demonstration of it being functional and what not. He lowballed me in person with his wife, but i let it slide. He takes it home, tries to build it, has trouble. Calls me nonstop while I am at my brother's wedding, i send him some texts on how to build it. I got him, and spent 3 hours helping him. One of the problems just to paint the picture is that he didn't plug the cpu cables. Now he's encountering some other problem, I didn't. He's been harassing me non stop on Facebook, and spam calling about getting a refund. I do not want it back. I was proved it worked, and was transparent about some testing limitations. He kept trying to guilt trip me talking about how he couldn't spend time with his wife, how he's just an old man and what not. I told him to leave me alone, and I blocked his number. This morning on fb, he messaged me about how if I don't comply, he'll get the police involved "and seek you out at your apartment". I asked him if it was a threat. he tried to play it off as him just giving options.

I informed my parents, and now they're super anxious about my safety. Yeah it was dumb to sell at my lobby, should've done it somewhere else. There was someone on my floor earlier going around knocking, and asking people. I am not sure if it was him. My parents got even more anxious, they now told me to not go down for a week.

I really am not sure what to do. Part of me feels uneased. I don't know what precautions I can do to protect myself. What should I do?