Paul DeMuth of Harmarville, Pennsylvania, fell behind on his student loan by $15,700 and the student loan company Navient called him about it 200 times over two years. He's now received a judgment of $300,000 against Navient for those calls--$1,500 per call in accordance with federal law. The company gets to deduct his original $15,700 debt, as a small consolation prize.

DeMuth is not the only one. A few years ago, Congress made changes to the Telephone Consumer Protection Act that vastly improved protections against unwanted phone calls. Since then, a growing number of consumers have won substantial amounts in court cases against the companies who called them, either through class action lawsuits or, as in this case, an individual suit. If you're getting unwanted phone calls from any company, you may well have grounds for a cash settlement. Here's how to find out, and how to cash in.

1. Know your rights.

As with anything from the federal government, the rules about unsolicited phone calls are complicated. Most of them apply to pre-recorded calls and calls placed by an auto-dialer rather than manually. Fortunately, the vast majority of companies making annoying calls do use auto-dialers, even if there's a human on the other end when you pick up. You're likely dealing with an auto-dialer if you hear a second or two of silence after picking up the phone, or if you get hang-up calls from businesses (a violation of the rules in itself). When in doubt, assume a call was auto-dialed. Only non-profit or political entities are allowed to make auto-dialed calls to a landline without prior written consent, and even they are barred from calling a mobile phone. One exception is emergencies--auto-dialed calls in an emergency situation, such as a school shut-down, are always allowed.

Debt collectors are also barred from calling you about someone else's debt, such as a former partner or family member or previous owner of your phone number. Once you've told them once they've got the wrong person, any further calls are illegal.

2. Tell them to stop calling.

Under the new rules, auto-dialed or robo-callers must tell you that can opt out of any future calls at the start of the call, and you must have the option to do so any time during the call. They must allow you to opt out by any reasonable means, such as saying "Don't call me anymore." They cannot require you to opt out in writing.

Telling them to stop calling can be worth a lot, because if they continue to call you after you do, you can collect $1,500 per call, that becomes a willful violation of the rules, worth $1,500 per call. A non-willful violation is still worth $500 per call.

3. Keep a record.

Should you record the phone call? Yes--if you get permission to do so from the person on the other end. In many states, it's also legal to record a call that you're on, even if you don't tell the other party. However, things could get sticky if the person on the other end is in a different state from you.

Whether you record or not, keep a written record of the call, when it arrived, and what number called you. Save any unsolicited texts your receive, which are also illegal, and any unwanted calls that get recorded on your voicemail. There are smartphone apps available that will help you keep track of incoming unsolicited calls (and make it super-easy to file a complaint with the Federal Communications Commission at the same time).

4. Ready, set, sue!

Once you have your written record of calls that were made to you, it's time to make annoying callers pay. Begin by doing a search on the name of the company calling you (FCC rules require callers to identify what company they're calling from at the start of the call. If your caller is a legitimate business and in the United States, you have a chance at collecting. Keep in mind, though, that scammy callers may falsely claim to be representing a well-known company. For example, a particularly annoying telemarketer was fined $120 million recently for fraudulently claiming to be calling from Marriott, Expedia, and TripAdvisor.

How do you sue? Many companies making illegal calls are facing class-action lawsuits so your simplest approach might be to find out if there is any such suit currently underway and add your name to it. Some of the judgments have been substantial, and usually only a small percentage of the people who could take part actually do.

Another fairly easy approach might be to sue your caller in small claims court. This could work well if you're suing for a relatively small amount and the caller is in the same state as you. If you do win a judgment, though, collecting could pose some challenges.

Finally, you could hire an attorney to sue the caller on a contingency basis. That's a little harder than just joining a class action, but not as hard as it may sound, since many law firms specialize in these types of suits. With a bit of searching you can likely find one in your area. And who knows? If some company has been really annoying you with calls, the next big settlement could come to you.