I need some advice on a flaky Executive Producer I'm working with. He's funding my short film or at least I should say he was. As soon as we got to post-production we met with the editor and the EP was supposed to pay him that day. It's a month and a half now and the EP said the check must have been lost in the mail. He stopped returning the editor's calls and now mine. I sent him messages asking if he doesn't want to be involved anymore, but no response. I called his Assistant twice and that finally got him to email me where he basically said, 'Hey what's up? Did you want something?' I told him to call me, but again no response. What can I do in the situation?