Nearly two dozen Pokémon Go Fest attendees are filing suit against Niantic, the game’s developer, seeking travel reimbursement following last weekend’s event, where most people were unable to play the game.

Chicago-based attorney Thomas Zimmerman said he was contacted by Jonathan Norton, a California local who traveled to the area for the event. Since then, Zimmerman told Polygon that “20 or 30” others have joined the class-action suit.

“He paid to fly out [to Chicago] for the festival, and had to wait for several hours in line, just like most everybody else in order to get in,” Zimmerman said.

When Norton eventually made it into Pokémon Go Fest, however, he — like everyone else —found that the game wasn’t working, leaving him unable to catch the promised rare Pokémon. Zimmerman told Polygon that this went against what Niantic advertised, which was that attendees would get hard-to-find Pokémon.

Niantic offered full refunds for their tickets on Saturday, just hours into the festival. All visitors also received $100 of in-game credit, as well as the promised legendary Pokémon. Zimmerman said that’s not enough. For people like Norton and others who traveled from out of town for Pokémon Go Fest, their expenses were much greater.

“We’re not seeking any relief with respect to the failure to get legendary Pokémon, because Niantic is offering that,” he told us. “But Niantic is not offering to refund people’s travel expenses for coming to Chicago. Most of the people came from out of state, many people from other countries — I talked to someone who flew in from Japan.”

Zimmerman insisted that his clients were asking for the amount of money spent on travel be covered more than anything else. Although Niantic made “promises that were not kept,” he said, the fact of the matter is that claimants say that the event did not provide the experience they expected.

“The issue is, what was promised, what was the incentive that people relied on and the representations that people relied on to buy a ticket and make travel plans and fly to Chicago to participate in this festival, would they have done that had they known that that was not going to be lived up to and they weren’t going to get the experience that was represented?” Zimmerman asked.

On the developer’s part, Niantic did extend the amount of time and locations that rare Pokémon could be caught throughout Chicago after attendees couldn’t manage to get the game working at the event itself.

Update: A spokesperson for Niantic issued the following statement to Polygon:

“Niantic does not comment on pending legal matters.”

Pokémon Go Fest: What Went Wrong