If you are individual to corp 1099 contractor, let the YC startup know that if you are not paid within certain time, you will be filing a report to State Dept.

If you are individual to corp 1099 contractor, let the YC startup know that if you are not paid within certain time, you will be filing a report to State Dept. of Labor and State Attorney General. Labor claims get much higher priority during liquidation. The $8K might be too high for small claims court other wise a lien through court judgement is very effective. Don't just walk away thinking it was cost of doing business and cost of your "stupidity". Such actions just enable people and companies like these to exploit others. As it is a YC startup and in SF, when you talk to anyone (offline) in SF area, just sneak in the mention how you were wronged by YC startup and founders. SF startup community is connected and words get around. Reputation is important. As a lesson for the next time, don't ever work for anyone on contract without taking advance payment and/or have more than one pending invoice. I work in financial data analysis and I use a saying. Never ever give someone benefit of doubt in discussions or business transaction or believe someone because of their background, pedigree, and how well known they are. If you do, there is a Madoff and LTCM waiting around the corner to clean you out. Edit: clarification. You should start with a letter/email to founders requesting payment within a certain time frame, for example 2 weeks. After 2 weeks, send founders another email/letter requesting payment within 3 days and mentioning you will take further actions if not paid such as reporting to DOL and AG both in CA and NY as well as reaching out to advisers, investors and shareholders of the startups. After 3 days, start a letter/email campaign pleading for intervention by the advisers, investors and shareholders of startup mentioning you prefer not having to resort to legal and regulatory means and hope they can intervene to resolve the situation and it doesn't reflect nicely on them personally being associated with such startup and founders... blah blah blah. Wait a few days and then file complaint to DOL/AG mentioning the steps you took to resolve the issue, mention names of all people you contacted.