The federal government has overpaid close to $70 million to thousands of past and current employees as of December, and it has reached repayment agreements for only about a third of the money, according to internal documents obtained by CBC/Radio-Canada.

Since the government consolidated many separate payroll systems into the Phoenix pay system last spring, tens of thousands of public servants have been underpaid, overpaid or not paid at all.

Many employees have reported problems getting paid correctly, and while Public Services and Procurement Canada has provided updates on how many cases are handled and left over from a June backlog of 80,000 cases, it hasn't detailed how much money was involved.

Employee got lump sum of $662K

But documents obtained by CBC/Radio-Canada reveal just how far the salary discrepancies go for thousands of overpaid public servants.

More than 26,000 employees have been overpaid a total of about $68.6 million, according to the documents. Only about a third of the money sent out in error — about $22.3 million — has been recovered, according to the documents.

While about half of the former and current employees across the country have been overpaid less than $2,000, some people have received more substantial payments.

At least 27 former or current workers — lawyers, project managers, researchers and senior advisers — have received more than $50,000 each in overpayments in the last year because of the Phoenix malfunction.

One ex-researcher even received, in error, a lump sum of $662,777. Another former senior adviser received several overpayments totalling $155,167, while a legal counsel was mistakenly transferred $81,714.

About one in every five cases of overpayment involves a former or current employee working in the National Capital Region.

'They haven't told me how much I owe'

One public servant CBC News spoke to said he has $40,000 in his bank account he's afraid to touch. He spoke to CBC News on condition of anonymity, because he is worried about his job.

He said that since May he's been receiving multiple paycheques, and though he notified the government immediately, the extra paycheques didn't stop until recently.

"I find it frustrating, because some pay periods I got three paycheques, and I know people who don't have any," he said.

Deputy Minister of Public Services Marie Lemay has asked anyone who believes they have been overpaid to contact the call centre. (Justin Tang/Canadian Press)

Two weeks ago, Deputy Minister Marie Lemay said these overpayments are a priority for Public Services and Procurement.

"Our goal is to clear up as many cases of these cases possible before taxes are issues," Lemay said at a media briefing.

She also instructed all employees who believe they have been overpaid to contact the call centre.

Call centre workers scrambling

But some tasked with dealing with the crisis say they are scrambling to solve a growing number of complex cases.

One worker at a call centre handling Phoenix-related issues, who asked to not be identified for fear of reprisal, said a lack of training exacerbates the problem.

He said he only received a day of training before he began to take calls.

''We don't give our clients the right information … we keep telling them [they] will get their paycheques in four weeks, then six weeks and then we just say the deadline is undetermined,'' he said.

Difficult to recover

At least $18 million of the overpayments were given to employees considered inactive, meaning their contracts are completed, they retired, quit or took an unpaid leave. Some haven't worked for the government in years.

Representatives from the Public Service Alliance of Canada and the Professional Institute of the Public Service of Canada (PIPSC) worry the government has lost control of the problem and may never recover some of the overpayments.

Stéphane Aubry, the vice-president of PIPSC, said it is "crazy" that the government is relying on the goodwill of public servants to report cases.

"They won't be able to recover everything. Employees move, some might even leave the country to take advantage of [the overpaid amounts]," he told Radio-Canada in French.

Paying money back not so simple

The public servant CBC News spoke with said paying the money owed isn't simple, as each extra paycheque has also deducted extra union dues and extra pension plan contributions.

He said he can't get a straight answer on what his repayment should be.

"They haven't told me how much I owe yet," he said. "So there is no way for me to even have an idea of how much I should be sending back."

How did we analyze the documents?

CBC/Radio-Canada obtained and analyzed documents pertaining to thousands of reported cases of overpaid salaries compiled in December 2016, including each amount overpaid, the date each case was flagged, as well as a code linking each case to a ministry department.