Visa ended its relationship with a large cryptocurrency card provider on Friday, causing thousands of people's transactions to be declined and scrambling to figure out how to access their money.
The card provider, WaveCrest, confirmed in an email to CNBC that it was required "to immediately close all Visa cards."
"As a licensed E-Money Institution, WaveCrest is required to safeguard funds to cover all of its issued electronic money and we can confirm that these funds are safe and available for redemption through other channels," the statement read.
Visa, a payment network, did not immediately respond to a request for comment.
Wavecrest provided its services to a number of crypto-card companies, including Bitwala, Cryptopay, Wirex and TenX. These companies convert people's cryptocurrencies into cash that is loaded on to a prepaid card, allowing people to use the currency for everyday transactions.
Now these cards are invalid.
Dmitry Lazarichev, co-founder of cryptocurrency card company Wirex, said he's received thousands of calls from frantic customers. He said his company has issued some 500,000 cryptocurrency debit cards to people across the world, although not in the United States.
"All the cards were shut down in one second," Lazarichev said, adding that WaveCrest hasn't been responsive. "We asked for more information, but they haven't provided any."
TenX, another cryptocurrency card company affected, tried to reassure users.