(NewsNation) — Starbucks might face its largest strike yet as unionized baristas accused the coffee giant of unfair negotiations at organized cafes.  

Starbucks Workers United, representing thousands of employees at numerous locations, is planning one-day strikes Thursday, coinciding with the company’s Red Cup Day, a popular event featuring holiday-themed reusable cups. 

The union claimed Starbucks unlawfully refused genuine negotiations on critical issues including staffing and scheduling during such promotions. 

On Red Cup Day, as a sequel to their 2022 strike, Starbucks Workers United members, joined by college students in what they call the Red Cup Rebellion, are organizing strikes complete with boycott calls and picket lines. 

Starbucks, in response, argued that the union was the party unwilling to negotiate fairly. Disagreements over meeting ground rules, such as allowing workers to participate via videoconference, added to the conflict.  

Starbucks asserted that the union hadn’t agreed to contract talks for months, while the union contended that Starbucks demanded workers accept illegal restrictions on their rights before meeting.

Although Starbucks Workers United successfully won elections at over 350 of the company’s 9,000 U.S. stores in the past two years, progress toward collective bargaining agreements has been sluggish.  

The union’s growth has significantly decelerated, and none of the unionized stores has reached an agreement with the company.  

The US National Labor Relations Board’s regional directors have filed more than 100 complaints against Starbucks, alleging illegal anti-union tactics such as store closures, firing activists and unfair negotiations at unionized cafes, Bloomberg reported. 

The agency accused the company of bargaining without the intention of reaching an agreement at the first two unionized stores.