DALLAS (CBSDFW.COM) – In the Sheets household, David Sheet’s wife usually handles their mail. But when she recently went out of town, Sheets took over the job.

“I said, ‘No problem! I got this! I’ll just drop it off at our office,’ ” Sheets said.

So Sheets dropped their bill payments in the outgoing box at the North Dallas Community Bible Fellowship Church in Plano, where he works.

“In total, about $10,000,” he said.

A week later, Sheets realized something wasn’t right.

“The checks were not clearing,” he told the Ones For Justice. “So I went to the post office to see, well, okay, are they picking up?”

Sheets said he was assured the carrier had retrieved the mail. Then the late notices began arriving, along with hundreds of dollars in penalties and fees.

All of them were postmarked the same day he began asking questions.

“I thought that seemed a little too coincidental,” Sheets said. So he started investigating by pulling church security video to see the mailman in action.

Day after day, Sheets saw the same thing.

“He deposits our incoming mail in the slot….and turns around and walks away,” Sheets said. The outgoing mailbox had not been touched for a week.

Sheets returned to the post office armed with the evidence. He said they assigned the carrier to another route, then told him there was nothing else to be done.

“They were very dismissive about it,” Sheets said.

So Sheets focused on the late fees.

Almost $500 had been tacked onto his property tax bill, so Sheets contacted the Carrollton-Farmers Branch ISD Tax Assessor-Collector and the Denton County Tax Office.

Again, Sheets outlined his case against the mailman.

“We did receive the refund from CFBISD,” Sheets said. “They did what they should have done because they knew we had fulfilled our obligation.”

But the Denton County tax office refused. Sheets says he was told they were not legally allowed to refund penalties and interest.

The tax office referred the Ones For Justice to the City of Carrollton and Denton County. A spokesperson for the city said it would cost more to investigate the issue than the refund itself, so it refused to do either. The county said if the post office would admit responsibility, it would issue a refund. That part is still developing.

As for the mail carrier, he was assigned to another route.

Sheets said he learned an expensive lesson at the hands of a mailman he claims lied to his face.

“We are taking our payments directly to the post office now,” Sheets said.