Okay so I purchased concert tickets for $200 and paid cash on sight. Now the seller is texting, emailing, and calling me claiming I never paid him. He says unless I pay him $200 he will be filling charges. I don't want to fork this crook over another $200 but I don't want this to turn into a battle because I paid with cash. What should I do? Does he have any credibility? I have no proof I paid him besides an ATM transaction. I also wanted to file a report on him but I don't know where he lives or even his last name. He also has now states he will be filling a civil suit in small claims court. What should I do?