Legal Question in Consumer Law in California

No doubt there is more to this than just the facts listed here, but most likely you can get some or all of your money back. Although no contract was "signed" you may have become bound by website terms you accepted. Or, you may have entered into an oral contract. Whatever your agreement, California law does not allow the enforcement of "penalties". So, assuming the venue was able to rent the space for at least as much as you were going to pay, they may be entitled to a reasonable sum in addition to any actual damages they suffered, but a court is unlikely to allow them to keep $4,000. Small claims court allows most claims up to $10,000. You can bring a small claims case yourself. More small claims information is available at http://limitedscopecounsel.com/small-claims/ Good luck!