CHICAGO (CBS) — Hundreds of support staff workers at schools in Palatine were headed back to work on Monday, after the union said the district threatened their jobs two weeks into a strike.

School nurses, special education classroom aides, secretaries, and other support staff at Palatine Community Consolidated School District 15 went out on strike on Oct. 16.

Although that strike has ended, the Educational Support Personnel Association said those employees only decided to go back to work because they were given an ultimatum by the district, not because they have agreed to a new contract.

The union said, when they met with the board on Sunday to negotiate a contract, the workers refused the district’s latest offer, and the district threatened to permanently replace employees if they didn’t accept the offer.

“It’s deceptive, untruthful, regressive and quite frankly, it’s illegal to give ESPA an ultimatum and threaten members’ jobs because the District 15 board is not bargaining with us in good faith,” ESPA President Angie Drazkowski said in a written statement. “We are extremely disappointed by the board’s actions, but are anxious to get back to the students that we love.”

ESPA said the 454 support staff who had gone on strike would return to work on Monday, and “will continue its fight for a fair contract in court.”

The union has filed several unfair labor practice charges against the district.

The superintendent welcomed staff members back Monday morning, saying “the Board plans to continue negotiating in good faith with ESPA with the hope that an agreement can be reached.”

“I want to emphasize that the ESPA staff members are part of our family. Staff, parents and students rely on them to support the important learning occurring in our schools each day, as well as the physical and medical care many need. The district is eager to welcome these valued staff members back to work, joining us in our mission to provide an excellent and safe education to our students,” Supt. Dr. Scott Thompson said in an email.

The union said the workers are disappointed, but anxious to get back to the students they love.

Watch & Listen LIVE