On Monday, Teamsters said a group of Amazon drivers and dispatchers in Southern California had joined the union and secured a pre-contract with their employer, an Amazon contractor, to be a first for the online store’s delivery network.

But Amazon said it had already notified the company that it was terminating its contract with the retail giant.

84 employees work for Battle-Tested Strategies, one of Amazon’s “delivery service partners” that delivers the “last mile” for Amazon. The drivers said the group, which works at the Amazon DAX8 facility in Palmdale, near Los Angeles, is the first of about 3,000 Amazon DSPs to form a union and reach an agreement.

“This particular third-party company has a reputation for underperforming and was notified of its closure due to poor performance long before today’s announcement,” Amazon spokeswoman Eileen Hardes said in a statement. “This situation has more to do with a third-party company trying to divert attention from its history of default.”

Battle-Tested Strategies did not immediately respond to emails asking for comment.

The drivers said battle-tested strategies agreed to voluntarily recognize the union. The union also said it had a contract with the company and that workers called on Amazon to “comply with the terms” of that agreement, although Amazon would not have to do so if it no longer had a relationship with battle-tested strategies. .

Amazon DSP drivers drive around in Amazon-branded vehicles and deliver Amazon products to Amazon customers, but they don’t technically work for Amazon—they work for contractors like Battle-Tested Strategies.

In a statement released by the union, one DSP driver at DAX8, Rajpal Singh, said he wants more accountability from Amazon when it comes to working conditions for subcontracted drivers.

“We deliver in an Amazon van dressed in Amazon uniforms, but when we reach out to Amazon, they ignore us,” Singh said. “We have a lot of support, we are a union, and now they need to be listened to.”

Unions, including the Teamsters, have struggled to organize Amazon’s huge delivery network, which includes not only drivers, but also warehouse pickers and packers – part of the company’s huge U.S. workforce of about 1 million people. Amazon’s organization is critical for drivers because Amazon can influence wages and working conditions throughout the logistics industry.

Last year, Teamsters announced the creation of a new division of Amazon within the union as part of their plan to break into retail.

Randy Corgan, director of the division, said in a statement Monday that DAX8 drivers are joining the union to “demand more from this company, including good pay, safe working conditions and respect.”

The union said drivers will vote in the coming weeks to accept their pre-contract with Battle-Tested Strategies. While details were not released, the union said the agreement includes “immediate pay increases” and “provisions that hold Amazon accountable for health and safety standards.”

The upstart Amazon Labor Union became the first working group to bring the Amazon venture together when it won an election last spring at JFK8 warehouse in New York. Now the union is trying to conclude the first collective agreement with the company.

This story has been updated with comments from Amazon.