The Federal Communications Commission on Thursday proposed fining the voice service provider Voxbeam Telecommunications $4.5 million for allegedly accepting “suspicious” call traffic from an unauthorized foreign provider.

The foreign provider, Czechia-based Axfone, was not allowed to transmit calls over American networks, the FCC said in a press release. The agency said it has found Voxbeam “apparently liable.”

Voxbeam’s actions allegedly led to “financial impersonation robocalls” that were made to American consumers “ using “non-compliant and long dormant accounts,” the FCC said.

Axfone is not listed in the agency’s Robocall Mitigation Database (RMD), which the FCC said is designed to block higher-risk providers from sending illegal robocalls.

Voxbeam and other voice service providers are barred from accepting call traffic from unlisted providers.

“Voxbeam has an obligation to block traffic from providers not listed in the RMD and an obligation to take all reasonable steps to protect consumers from likely scam robocalls — in this case tens of thousands of foreign calls coming from accounts that have not generated a call for years,” the press release said.

Axfone has never been listed in the RMD and used a Voxbeam account that had not carried call traffic since 2018.

The tens of thousands of calls Voxbeam transmitted for Axfone were placed between March 31, 2025 and April 3, 2025, the FCC said. Many of them spoofed fraud prevention and customer service phone numbers for Bank of America, Chase Bank and other financial institutions.

The FCC launched its probe after a bank whose customers received the scam calls complained to the agency.

The fine is not yet final, the FCC said, because Voxbeam will be given the chance to respond before a permanent decision is made.

Voxbeam did not immediately respond to a request for comment.