You could sue the company you are subcontracting for to recover the money. When there is an agreement (written or oral/verbal) to do work for someone and you do the work but they do not pay the agreed-upon amount, they have committed breach of contract. For smaller amounts (less than the maximum cap for your local small claims court), you may wish to sue in small claims, which is faster, less expensive, and simpler than other courts. If your business is an LLC or corporation, you will need an attorney to represent you, even in small claims.