The holiday season presents a variety of economic stresses – from buying gifts and decorations to attending pricey holiday parties. However, for freelancers, the stresses are magnified by scofflaw clients.

Some 40% of freelancers will start the holiday season with $2,850 in overdue invoices, according to new research by FreshBooks, a firm that provides billing and accounting software. And that depressing figure is just the national average.

In some states, outstanding invoices add to considerably more. In New York, for instance, the average freelancer is owed more than $4,244. In Delaware, the value of overdue invoices adds to $4,094; in New Jersey, it is $3,951.

Getting paid at all can be a challenge. More than half of the invoices written by freelancers in South Dakota, Mississippi and Vermont are late. Roughly one-third of invoices will never be paid at all, according to FreshBooks. This new research, gleaned by looking at the status of more than 10,000 invoices sent through the company’s billing platform, confirms earlier studies that indicate that roughly one-third of freelancers were unable to collect payment for at least a portion of their work.

“There is an epidemic of unpaid invoices in the freelance economy,” says Lamine Zarrad, chief executive of Joust, a banking and invoicing service. ”Freelancers don’t have the collection power of a corporation behind them. They’re left to their own devices. Unfortunately, that means a lot of them don’t get paid.”

Trust not

To be fair, the problem sometimes starts with the freelancer. Because many are accustomed to working for traditional employers, who are bound by enforceable government rules and regulations that demand paying workers within a reasonable period of time, they can start out too trusting. Instead of expecting written contracts before starting work, four in 10 freelancers work via verbal agreement, according to a 2015 survey by the Freelancer’s Union.

With nothing in writing, it’s extremely difficult to enforce those deals, says Zarrad. Consequently, the freelancer has little recourse when the client says the work wasn’t done to specifications, wasn’t acceptable, or simply ignores your invoice.  

Improving the odds

Freelancers who want to improve their odds of getting paid have a number of ways to do it.

Get it in writing: Never start a job without a written agreement. You don’t necessarily need a formal contract every time. However, you should have at least an email that spells out the terms of the deal.

If, for example, you’re designing a web site for someone, your agreement should say whether you’ll be paid by the job or the hour. If it’s by the job, you should specify how many pages the site will be; what services (i.e. copy, images, headlines, etc.) are provided by the contractor vs. the client; what will be included in the site; when it will be completed and when payment is due.

Think through the “what ifs”: It’s also smart to put in a contingency clause spelling out what happens if the client’s needs change. What if the client wants something different than was originally specified, needs more pages, or simply decides to table the project? Does the client pay a “change” or “kill” fee? How much is due for adding pages or providing services not anticipated in the original agreement?

Written confirmation: Naturally, you can put all of this into a formal contract. However, if you simply want to email the terms, make sure that the client accepts them in an email, rather than with a simple verbal okay. You may need the paper trail later.

Progress payments: If you’re working on a complex project that’s likely to take several months to complete, it’s reasonable to require an up-front deposit and/or progress payments as the work nears completion. The amount and timing of these payments should be spelled out in the written agreement.

Invoice promptly: If the freelancer shows no sense of urgency when sending out bills, the client is also likely to be less prompt with payment. Send an invoice the moment a project is complete, suggests Matt Baker, vice president of strategic planning at FreshBooks. Make sure that your invoice is professional looking and includes a due date, he adds.

Polite reminders: When an invoice hasn’t been paid within a week of the due date, it’s time to send a gentle reminder. And, remember your manners. FreshBooks research found that using polite terms, such as “please” and “thank you” significantly increased the odds of getting paid.

Public shaming: When a client refuses all reasonable requests, some freelancers turn to public shaming by bringing the battle to the client’s social media accounts. With a large company that cares about its reputation, this may be all that’s required to get payment. Not surprisingly, though, it’s likely to sour any continuing relationship. On the bright side, you probably don’t care about losing a scofflaw as a client.

Insure payments: Joust offers a product that insures that you get paid. If you invoice through the site’s system, which automatically produces a contract accepted by both parties, you can pay a 1% fee to insure you’re paid within 30 days. If the client doesn’t pay you, Joust will. If you want immediate payment, the site will charge a 6% fee, but pay you the remaining invoice amount within seconds.

Take it to court: If all else fails, you can take clients to small claims court to collect. This does not generally require hiring an attorney. Most actions can be filed online by filling out a short form and paying a filing fee. You may, however, need to establish that your client does business in the district where you’ve filed your claim. And it’s important to have the appropriate documents to establish what you’re owed – i.e. that ever-important first step of getting your deal in writing.

Related: You may also want to check out, 5 Ways to Make $1,000 by Christmas and 8 Ways to Make Money Renting Your Stuff.