ok guys im freaking out here i really need somebody to tell me what to do. i sold my dj system on craigslist to some guy and he picked it up from my house. i showed him that everything works, he gave me the money and i shook his hand and said pleasure doing business with you and expected it would be done. now hes texting me saying that something is not working and its my fault and i either fix it or give him his money back. the deal is done but im scared this guy might come back to my house or something what should i do???