Eric, do you have other projects on hand? If yes, drop it. If no, complete it, and put it on your showreel. Who knows, maybe the director will call you for future work, and you can renegotiate your terms better.
Ask them for some money, but don’t be too hard on them. If they refuse, continue ‘working’, but look for other projects. Drag your heels if you can, and find excuses for missing deadlines. If they don’t pay you something now, they deserve it.
Hope this helps.
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