Three weeks from Christmas and there's no guarantee Canada Post letters and packages will arrive in time. Canada Post has suspended its delivery guarantee citing significant backlog and delays after more than five weeks of rotating strikes across the country.

"We came into December overloaded, backlogged. We've been working through that but more and more comes and it's more than what we're able to get out the door." said Jon Hamilton of Canada Post.

The federal government passed back to work legislation more than a week ago; in an effort to salvage deliveries by the holidays.

"They know this is our busiest time of year; right now we are three times the number of parcels and mail that we would be seeing in our yards at this time of year." said Hamilton of the Canadian Union of Postal Workers' on-going protests and demonstrations. Hamilton pointed to what he called several illegal strikes stalling operations in major facilities including Toronto.

Ottawa's postal workers' union CUPW STTP isn't buying it saying the union is exaggerating backlogs.

"This is a manufactured crisis by Canada Post and I think Justin Trudeau fell into the trap." said Dave Woods, CUPW Ottawa Vice-President.

The local's president, Ian Anderson, said "We don't want to hold the public hostage...This backlog they had, I don't believe it was as extensive as what they're saying - the mail was still going out. And we should still be on rotating strikes as far as I’m concerned."

The local union says despite 11 months of negotiations Canada Post knew all along they could wait them out until Christmas; pressuring the government to step in

Employees inside Canada Post say they're overworked; often forced to work 8-10 hours only being paid 5 or 6.

"Everyone on the front-line - if you see it, they're crying every day." said Naveed Khan - Canada Post employee of 34 years.

As Canada Post battles increasing demand for deliveries during its busiest season, Hamilton says:

"We'll continue to communicate with our customers we'll put bulletins out on our website, we'll work with all the customers selling things today, but we are seeing a backlog growing this week. Parcels continue to be delivered, we just aren’t in a position to guarantee those delivery windows at this point. Some may arrive within the window while others won’t due to where they were shipped from, where they were going, disruptions, etc."