[greenyoda]

Talk to a lawyer to find out what your options are. If the customer has enough money or assets, it may be worth suing them. There might also be grounds for filing criminal charges, e.g., theft of service.

It's possible that all it would take to get paid is having your lawyer send a letter to the company demanding payment (plus legal fees), and explaining that lack of payment will result in legal action.

Of course, if the total amount in dispute is less than thousands of dollars, it may not be worth your time and effort to sue. In that case, you could consider turning the debt over to a collection agency, or just doing nothing. And definitely never do business with this customer again.