Even the most organized and financially responsible person can see a debt go into collection. It might be a single overlooked lab charge from a complex medical issue or a bill never forwarded to you after a move. The question is what to do about it once you find out.

When a bill goes into collection, there are four interested parties. There's you and the creditor — the original entity you owe, be it a large bank or a small business. There might also be a collection agency, which may be acting on the creditor's behalf or may have acquired the old bill from your creditor outright. Finally, there are the credit scoring agencies, which report the information they get from creditors and collectors.

Ignoring collectors is not recommended. That leaves three good options. You can pay the bill in full. You can try to settle for less than you owe. Or you can dispute the bill and refuse to pay.

How should you proceed? I asked Bruce McClary, vice president of communications for the National Foundation for Credit Counseling. He's also worked for lenders, for a collection agency and as a credit counselor, so he's been on all sides of the table when it comes to collections.

The most important question, according to McClary, is whether you owe the debt fair and square.

If there are significant extenuating circumstances — if you don't recognize the time, place, amount or account, if previous bills were directed to the wrong address, if you were hospitalized at the time, the victim of a natural disaster or identity theft, or you believe you've already paid the debt off — then gather your documentation and prepare to either dispute outright or try to settle the debt for less than face value.

If not, the best recourse is to pay in full, or pay enough to get it current, whichever is feasible. Here are some things to know.

If it's a medical debt, the repercussions are not as great. Newer credit scoring models put less weight on medical debts, including those in collection.

Once a debt in collection is settled, it continues to have a negative impact on your credit report for up to seven years. You can lessen the impact of a collection during that time and raise your score, McClary says, by opening more credit accounts and keeping them up to date.

If the original debt was less than $100, an account in collections is unlikely to significantly ding your credit score.

If you dispute a collection with a creditor or collection agency, you should contact the credit scoring agencies. Send a letter by certified mail “return receipt requested” to Equifax, Experian and Trans Union, the three credit reporting companies. Include any documentation that bolsters your position. Sample letters are available at Consumer.ftc.gov.

Once you've settled a debt, wait 60 days and then pull your free credit report from annualcreditreport.com to make sure the information has been updated.

Your negotiating position can vary depending on who owns the debt. Big banks and credit card companies aren't going to be very flexible. On the other hand, you can try calling an old landlord, a dentist or an exterminator and offer a settlement in return for taking the bill out of collections. Make sure you get this in writing (what is sometimes called a “letter of deletion”).

If the debt has been “charged off,” that means it's been sold to the collection agency, likely for pennies on the dollar, and your settlement negotiation should be with them.

Anya Kamenetz welcomes your questions at diyubook@gmail.com.