Milk, eggs and bacon have expiration dates and so, delightfully, does debt.

Creditors and third-party debt collectors typically have around six years to track down consumers and sue them. They don't typically go that far when the magic date arrives, but if they do, consumers can ask a judge to dismiss their cases based on their state's statute of limitations.

Pat O'Connor wasn't aware of the timeline until her husband, John Miller, received a letter recently from a debt collection agency asking him to pay a "settlement offer" of $68.19, graciously cut down from a $136.38 balance once owed to AT&T Broadband.

The problem, O'Connor ranted to The Desk, is that they'd never been customers.

The Desk suggested O'Connor ask the collector, Credit Bureau Collection Services Inc., to attach a date to the account. The year, 2000, it turns out, was a debtor's equivalent to a darn stinky pint of sour cream.

In Oregon and Washington, the statute of limitations on debt from written contracts is six years from the account's last activity. Statutes vary state to state; for instance, the limit on credit card debt is three years in Washington and six in Oregon.

O'Connor might be dealing with what folks in the credit counseling community call a zombie or scavenger debt collector. These bill collectors buy up old, typically charged-off accounts for a fraction of the original amount and try to track down the debt -- often after it has or is about to expire and sometimes, even after it's already been paid.

Receive a collections letter that doesn't compute? Jog your memory with a look at your credit reports (access free reports from Equifax, Experian and Transunion yearly at annualcreditreport.com). If the debt isn't listed, that's an indicator that something may be fishy, said Jan Safley, director of Consumer Credit Counseling Services of Southern Oregon.

Questionable mail?

If you receive something suspicious in the mail — say an offer for an auto warranty or mortgage insurance — contact the U.S. Postal Inspection Service. The federal agency accepts consumer complaints and can provide the complaint history of a mailing that’s potentially fraudulent: Details: postalinspectors.uspis.gov/ or 877-876-2455.

If the debt is listed, check the date noted as the account's last transaction.

"This is just a huge issue right now," said Safley. She notes that consumers feel particularly vulnerable in this economy and that people who have good credit or who are attempting to repair a low score may pay off an outstanding account just to be safe.

"That just encourages these guys who buy up all this debt real cheap," she said. "If they can get just a few people to send them money, it's pretty lucrative."

And, like in the movies, zombies can be tricky.

Debt collectors may be able to reset the timeline if they can get consumers to admit the debt is theirs or persuade them to pay some small amount of it.

Safley and others recommend that you write -- don't call -- to dispute a claim and ask for proof of the debt. For a sample of what such a letter might look like, search online for "debt validation letter."

If consumers know the debt is theirs and decide to pay a portion of it, make sure to get the deal in writing, she said. Sometimes another collector will buy up the remaining debt and come back asking for the full amount. Also, she said, know that paying partial amounts will hurt your credit score and means you must report the gift -- yep, that's the wording for the difference between what you owed and what you agreed to pay -- to the IRS.

To be sure, in O'Connor's case, CBCS simply may have gone after the wrong person for a valid debt. The Desk's calls to CBCS to get at why it was looking to collect on a nine-year-old bill were not returned.

O'Connor informed the firm in writing within 30 days of receiving the letter that CBCS had the wrong person and that the contact should end there. If not, a tweak to the state's debt collection laws will allow the Oregon attorney general to follow up with the company if it makes repeated attempts to contact O'Connor after being notified it had the wrong person.

Although the Columbus, Ohio-based company is legitimate, it has racked up a raft of consumer complaints in recent years.

The Ohio attorney general's office has collected 516 consumer complaints against CBCS since September 2004, while the national Better Business Bureau has received 652 in the past 36 months, of which 586 pertained to billing and collection issues.

Oregonians have filed 16 complaints with the state's AG office, all with similar issues as O'Connor's. Online, dozens of consumers compare stories about receiving similar letters -- all with balances from companies with which they've never done business.

Have your own consumer complaint? Contact Laura Gunderson at The Desk: 503-221-8378 or Read The Desk online at blog.oregonlive.com/complaintdesk