What is the law about working and not getting paid?

In Washington, businesses must pay workers on regular established paydays no less than a monthly basis, subject to some wrinkes if a union collective bargaining agreement is involved. The Washington Department of Labor and Industries has a workplace rights section (linked below) on payment of wages and a regulation on payment intervals (also linked below).

Were you working as an employee or as an independent contractor?

If you were an employee, you can report not being paid to L&I.

If you were an independent contractor, you likely would have to sue if the company would not voluntarily pay you.

When an employer stiffs you, most states have a Labor Commission or Board that will help you for free to collect the wages and sometimes, with interest and penalties.