Uber, the fast-growing San Francisco app-based transportation startup, has another problem to deal with in Seattle: Angry drivers who say they’re being treated like slaves.

Former and current Uber drivers gathered on Sunday afternoon to discus what they call “unjust working conditions.” They met to talk about a possible union and address concerns about Uber’s treatment of drivers, specifically when it comes to deactivation from the company’s network.

William Anderson, a former Uber driver, notes here that once his rating went from a perfect 5 stars to 4.6, Uber shut down his phone without warning.

At Sunday’s meeting, our news partner KING5 spoke with former Uber driver Yedidta Seifu, who expressed frustration with the company — especially given the money he’s invested to become a driver.

“According to Uber, we’re partners — but they treat us a little better than slaves,” he told KING5.

Brooke Steger, Uber’s Seattle General Manager, provided this statement when asked about the alleged unfair working conditions:

“More than 50% of Uber partner drivers are former taxi drivers because they feel safer knowing who is in their car and, with Uber, they don’t need to carry cash. These drivers also migrate to the Uber system so they can own their own businesses and have flexibility in their schedules, in addition to making more money. The taxi industry special interests who put on this event have continually failed to improve the wages and working conditions of taxi drivers, which is the exact reason why drivers partner with other technology platforms.”

Most people at the meeting were professional drivers who partner with Uber via its higher-end UberBLACK service. That’s separate from UberX, which is Uber’s cheaper option that allows everyday drivers to use their own vehicles to shuttle people around town.

UberX, meanwhile, is set to be regulated after the City Council voted last month to cap the number of vehicles that services like UberX and Lyft can have on the road to 150 — a limit that Uber, along with Lyft, has expressed disappointment with. But those regulations could be suspended and put up for a city-wide vote if a coalition group can collect enough petition signatures by April 18.

Representatives from the Western Washington Taxicab Operators Association (WWTCOA), who recently filed a lawsuit against Uber for “unlawful and deceptive business practice,” came to Sunday’s meeting in support of the Uber drivers. Mike O’Brien, a Seattle City Councilmember who sits on the committee for taxi, for- hire and limousine regulations, was also in attendance Sunday. Fellow Councilmember Kshama Sawant planned to go, but MyNorthwest.com noted her absence.