Workers at autoparts supplier TDS Automotive reportedly rejected a new deal on Monday, extending a strike that forced General Motors of Canada to idle two plants in Ontario and send about 6,000 workers home.

Canadian Auto Workers spokesman Dan Garvey told Reuters union members voted against a deal that the union recommended, but did not discuss details about what was offered.

“Members have decided to go back to the (bargaining) table for better wages after over a year of salary freeze and we are committed to whatever it takes to reach a reasonable settlement,” Garvey said, according to the report.

Contract talks between TDS and its union broke down on Sunday night and the roughly 550 workers hit the picket lines, Reuters said.

“The issues were money, benefits, language, a whole pile of stuff, but obviously the breakdown was at the monetary end of it,” Garvey reportedly said earlier on Monday.

According to Reuters, General Motors scrapped the second shifts at two Oshawa plants because of a shortage of parts after TDS workers walked off the job – the supplier makes just-in-time deliveries of subassembly components for steering columns, among other parts.

GM spokeswoman Pam McLaughlin told the news agency GM’s third shift was still scheduled at Oshawa Plant 1, which makes Chevrolet Impala and Monte Carlo models. Oshawa Plant 2, where the Buick Regal and Grand Prix are made, has only two shifts.