That is exactly what they did, the user used a credit card with their damn name on it, while Proton even allows you to send them cash money for the service. The FBI filed a MLAT (Mutual Legal Assistance Treaty) request which was processed by the Swiss Federal Department of Justice and Police. The Swiss gave a legal binding order to Proton to hand over information that they had, the only information that was handed over was the payment identifier. I don't get why people get hung up on a company complying with a legal order by their justice system, especially with Proton that could not hand over any more information.