I'm a freelance Graphic Designer, web developer. Recently I was asked to do some development and draft several images for a large comic con that is being held in the area. My intention was to work with them on terms for compensation. They are now saying that I will not be compensated at all. Compensation aside, they are now using my images for Television Commercials, Marketing Materials, on the event website, as well as on their corporate website. Some of these images, I have given permission to use on the event website, but I've given no such permission to use for printed marketing and film, or on other websites. I also believe it is their intention to sell some of the images at the event. I have reached out to them repeatedly asking them to work with me to define the terms of acceptable usage in addition to the aforementioned compensation. Now the event is two weeks away and I'm wondering what my legal standing is and what my next move should be. Any feedback would be greatly appreciated.