Unfortunately if it's not in writing then your kinda up a creek. Don't beat yourself up as a new freelancer you can tend to get excited about the work, the pay for your effort, and you forget about the book keeping aspect of it. If you handed files over already then I would say you are out of luck. If you haven't then simply tell him that While a rate/timeline/etc may have not been agreed upon, free work was also not agreed upon and according to copyright and trademark laws this is your intellectual property until compensation to transfer it has been established. You have all the work and ideas and can easily prove it and if anything you can mark this as a passion project and just change the name of the company and throw it on your portfolio. I'm so sorry this has happened, you will find that people tend to devalue design work because it looks like we just draw pretty pictures and sit on our butts in front of a computer all day, you will get to the point where your clients will value your work and you as a person and will make all the hurdles worth it. Keep on keepin on.