JPMorgan Chase & Co. has been sued in federal court for allegedly charging “surprise fees” when it suddenly stopped letting customers buy cryptocurrency with credit cards earlier this year. Attorneys said the company began treating the cryptocurrency purchases as “cash advances” instead of classifying them as genuine purchases.

The case is Brady Tucker et al v Chase Bank USA, U.S. District Court, Southern District of New York, No 18-3155. It was filed on Tuesday April 10th, 2018 as a proposed class action lawsuit. The lawsuit says that Chase charged clients markedly higher interest rates and fees without first alerting the customers, which violates the US Truth in Lending Act.

Chase would give no pubic comment on lawsuit.