As major online travel agency Booking.com faces reports of payment failures in Europe and Asia, some Japanese hoteliers are planning to file a class-action lawsuit against the company.

Hotel owners say that over the past few months, Booking.com has failed to promptly transfer customer payments to the hotels, essentially leaving hotel bills unpaid for days or even months.

Hirotaro Kato, the lawyer taking on the class-action lawsuit, said around 40 people have consulted with him about Booking.com’s payment failure, of which three have decided to take part in the lawsuit. He plans to file the lawsuit sometime this week.

One of the prospective plaintiffs is Masahiko Matsuo, the head of Kazaya Group, a company that operates several hotels around central Japan. He says that his hotels have experienced delays in payments since June.

The situation got worse when he was notified via an email from Booking.com that, due to system maintenance, the revenue from the end of June and all throughout July would not be transferred until August.

Given that his hotels rely mostly — if not entirely — on Booking.com for reservations, this failure to pay in time meant that the hotel had essentially no income for the entire month of July.

“They didn’t end up paying for our July revenue until the very end of August,” Matsuo said. “I have still yet to receive payment for our September revenue, yet they continue to charge us commission fees for using the platform.”

He says that Booking.com still owes his company around ¥6 million.

“There was also a time when I had to ask some of my workers to wait a couple of days for their paycheck since we couldn’t get the money,” Matsuo said. “Thankfully, my employees were okay with it but I have heard that this has led to people quitting at other hotels.”

He says that, in a group chat with hoteliers struggling with the issue, other hotel owners have shared that they are on the verge of bankruptcy or that they haven’t been able to pay their employees for three months.

Matsuo stressed that he feels that very little has been done from Booking.com’s side to address the issue.

“Initially, the only people I could contact were the call center staff who had no idea or control over the situation,” he noted. “I feel that the head of the Japan office or something should be taking responsibility and coming forward to explain what is happening.”

Booking.com issued a statement on their website on Tuesday, apologizing for “updates to their payment system” causing issues for some of their partners. They explained that the problem occurred during a planned maintenance operation that they were carrying out in order to transfer over to a new payment system.

“Most payments have resumed but due to unforeseen technical difficulties, there are still delays with some of our partners,” the statement read. “We are urgently working to resolve these issues.”

The statement was released following reports about the possibility of a class-action lawsuit against the company.

Headquartered in Amsterdam, Booking.com — one of the largest online travel agencies in the world — is facing similar complaints across the globe. The Guardian reported that hotel owners have been left unpaid for months in Southeast Asia and Europe. The BBC also reported on similar issues affecting hotels in England in August.