John Sibbet said he always pays his bills on time. So when Washington Mutual told him they had not received his monthly credit card payment after it was declined at Giant Eagle, he was so mad that he canceled the card.

"I told them 'I swear on my mother I mailed the check,'" he said.

Mr. Sibbet soon discovered that none of the 20 or so bills he mailed New Year's Day from Lawrenceville made it to their respective locations.

Mr. Sibbet is one of many residents from in and around Lawrenceville that report the mail they dropped off in Lawrenceville mailboxes around New Year's Day was never delivered.

He said the U.S. Postal Service told him they had received more than 100 similar complaints.

Tad Kelley, a spokesman for the U.S. Postal Service Pittsburgh District, said that an unknown amount of mail dropped in Lawrenceville boxes from Dec. 31 to Jan. 2 is missing.

"It's a small amount of mail compared to the mail we dispatch daily," he said.

Mr. Kelley said the postal service is "conducting an exhaustive search" internally for the mail. "Generally in these situations the mail we do find," he said.

Dan Mihalko, a spokesman for the Office of the Inspector General, said his agency learned of the missing mail yesterday and started investigating.

Until then, customers whose mail went missing are fretting over late fees, bad credit reports and even possible eviction.

Darlene Arraujo, a Lawrenceville resident and stay-at-home mother of two, said she worries she will be evicted because the money order she sent on Dec. 31 to pay her rent never made it to her landlord. She said she can't afford the $30 fee to put out a trace on the money order.

"I don't know what I'm going to do, what I have to do," she said. "I just hope they find it soon."

Executive Director Tony Ceoffe of the neighborhood group Lawrenceville United said his organization had received about eight calls from residents whose mail was missing. He said he was concerned that residents would be hit with late fees or that late payments could adversely affect their credit reports.

"What about these poor people living paycheck to paycheck ... they're going to be hit with all these late fees," he said.

Craig Watts of Fair Isaacs Corp., creator of the FICO credit score, said it's up to the creditor to determine whether they will report a late payment to the credit bureau, so a late payment won't necessarily affect a person's credit report and might not be reported to a credit bureau immediately.

He recommended that people check to see if their bills have gone through and to check the next bill to see if there are late fees or late payments reported. After that, he said. people should follow up by checking their credit report a week later and a month later.

Mr. Kelley said the Postal Service can issue a letter to customers confirming for creditors and others that mail went missing if they call the Postal Service at 412-359-7900.