By Chris Tye

CHICAGO (CBS) — As calls for changes at the top continue and delivery delays add up, CBS 2 continues to investigate what is behind massive failures inside of the United States Postal Service.

When the holidays end, so too does employment for hundreds of postal workers brought on seasonally, but in a year when the delays have been unprecedented and need for manpower so great, some workers were surprised to learn their reason for dismissal was because of a “lack of work” and they had been boxed out of open positions.

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“Right now, just to be blunt, we are short of manpower,” said June Harris, president of the National Postal Mail Handlers Union, Local 306.

Whether it’s walking the route or working the sorting machines, bodies are fewer and delays are longer.

The shortage is short-circuiting service.

“So for six weeks, I got no letter mail,” said Debbi Roy Martinez.

Just this week the post office posted jobs for automotive techs, garage assistants and city carriers for various Chicago locations.

“And I think all of our crafts are short of manpower,” said Harris.

What is not being delivered: answers to questions about service delays.

“There was no reason whatsoever that was given,” said Roy Martinez.

Several hundred workers were recently terminated at a sorting facility at O’Hare, where 500 career employees, 122 mail handler assistants and 200 “peak season” additional assistants work.

That is until last month.

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“They have been let go due to the post office being over our contractually mandated 24.5% allowance of MHA employees,” said Harris.

But many, like one who did not want to be identified because he would like to be rehired, said he wasn’t seasonal.

“I was not a seasonal worker,” he said. “There were lots of us that were not seasonal workers.”

The post office and union say they were, and a union rule blocks him from most open jobs.

“We’re not allowed to move people into other peoples crafts,” said Harris.

His termination paperwork cites Action Code 357 — lack of work.

So, the post office, short on manpower with jobs to fill, claims “lack of work” is reason to terminate him. And a union bylaw prevents him from drawing other paychecks.

“I can understand the confusion,” said Harris.

It’s confusion for what happened last month and about what comes next.

“For that to be taken away with no excuse, that was really hard,” the former employee said.

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A spokesperson for the USPS says this was not a mass layoff. It was the holiday season ending and planned seasonal workers being let go as planned. The union says these rules protect their members from being replaced from other departments.