The agency staff at Dover Fueling Solutions in Dundee were told they would lose their jobs on Monday.
One of those affected, who did not want to be named, said around 180 posts have gone and workers are "devastated".
He said he is now worried about how his family will cope, adding the invite to the meeting about the lay-offs included a picture of Santa.
The worker, who lives in Dundee, has been at the company for almost two years but will now be out of a job on Friday.
He said: "It's made me more nervous for after Christmas because I have two young kids and times are hard as it is without worrying about money.
"I want people to know how unfairly we've been treated. There wasn't even a proper apology from management or team leaders, which would have went a long way."
Bob Macgregor, Unite union regional official for Tayside, said staff are employed through agency EN Recruitment.
He said: "Obviously people are upset. It's close to Christmas, nobody wants to lose their job at this time of year, but I think the company are trying to protect the permanent employees."
Mr Macgregor believes the decision to cut agency staff has been taken following a dip in projected orders for the first three months of next year.
A Dover Fueling Solutions spokeswoman said: "Based on the cyclical nature of our business, we don't comment on any temporary employment within the organisation.
"Our orders are within the strategic lines of our business. This is a cyclical business and we do have growth year-on-year."
EN Recruitment declined to comment.