Coinbase has been hit with a proposed class action lawsuit claiming the San Francisco-based digital currency exchange has unlawfully held onto some unclaimed cryptocurrency that account holders have routed to others’ email addresses.

The lawsuit, filed March 2 in the U.S. District Court for the Northern District of California by San Diego lawyer William Restis, claims that Coinbase, which allows its account holders to send cryptocurrencies to a recipient’s email address, has violated California’s Unclaimed Property Law by failing to deliver cryptocurrencies to some people who didn’t already have Coinbase accounts.