They sort of have you by the short hairs since you agreed to work under the table. If you turn them in, then you are going to have to own up to paying taxes and possibly affecting your social security income (if you are collecting). Do you have anything in writing? Do you have time cards or invoices you have given to them. You could be considered an independent contractor and like any vendor, sue in small claims court for payment....but again, did you report the income? I would get whatever proof of work you have and confront them directly. Just give them a deadline ...don't threaten. Ask them what the hold up is...could be they are waiting to be paid first. Remember that you have the rights to any work you have done that you have not been paid for...so depending on what you do for them, be sure to remove documents and such from the computer, etc. They can have them back after they pay you.

Chalk it up to a lesson learned. I wouldn’t work another day for them.

Don't even say goodbye-report them to State Labor Board