Starbucks (SBUX  ) union workers have filed a complaint against the company regarding what Workers United says was an "illegal" closure of a New York Starbucks location. The store being permanently closed is one of three Ithaca, NY, Starbucks locations that voted to unionize in April. Ithaca is the first U.S. city to see every Starbucks unionize.

Over the past six months, more than 230 Starbucks locations have filed unionization requests with the National Labor Relations Board (NLRB). There has been ongoing tension between company management and executives and the activists and union officials, but the union has come out ahead so far: around 100 stores have voted "yes" to the union, while just 14 have voted "no".

The employees at the College Avenue Starbucks in Ithaca were given one week's notice of the closure of their workplace, and the location is scheduled to close on June 10. Starbucks says that the closure is not related to the store's unionization.

"Seems like blatant and illegal retaliation for one of the most profitable and militant union stores in Ithaca," said College Ave. barista Nadia Vitek in a statement. "Assuming we'll be transferred to other stores in Ithaca, our hour cuts are going to be even worse - they'll do anything for us to quit."

Prior to the vote to join Workers United, employees at the store went on strike in relation to "a waste emergency caused by the overflowing grease trap," the union reports. The company says that the grease trap overflow is the reason why the store is being closed, but workers say that the subsequent strike is the real motivation behind the closure.

"This is clearly retaliation for our small grasps at dignity as workers, but our strike showed them what power we have," College Ave. Starbucks employee Benjamin South said in a statement.

A spokesperson for the company told Bloomberg that Starbucks is closing the College Ave. store due to issues with the facilities, as well as staffing problems with time and attendance.

"We open and close stores as a regular part of our operations," Starbucks told NPR in a statement. "Our local, regional, and national leaders have been working with humility, deep care, and urgency to create the kind of store environment that partners and customers expect of Starbucks."

"Our goal is to ensure that every partner is supported in their individual situation, and we have immediate opportunities available in the market," the company stated.

Workers United alleges that by closing the College Ave. location, the coffee chain is not only illegally retaliating against workers but also violating its obligation to negotiate the closure in the hopes of discouraging future unionization at other locations. The union filed an unfair labor practice charge with the NLRB on Friday, June 3.

"It is a clear attempt to scare workers across the country by retaliating against its own employees," the union wrote in a statement.

This complaint is one of 175 that the union has filed against Starbucks. Several of those complaints have involved allegations of retaliatory firings of labor organizers and activists by the coffee giant, and many of the complaints against Starbucks have been upheld by the NLRB.

For its part, Starbucks has denied all wrongdoing.

Workers United hopes to win a federal court injunction to stop or reverse the College Ave. store closure.

"We won't let Starbucks get away with retaliating against us like this," College Ave. barista Evan Sunshine said. "Whatever it takes, however long it may take, we will persevere."