If you pay Proton Mail for a service, they may hand over the payment data in response to a court order: https://www.404media.co/proton-mail-helped-fbi-unmask-anonymous-stop-cop-city-protestor/
@cliffle @evacide All companies have to comply with the jurisdiction in which they are registered. In this case they complied with Swiss law, not the FBI directly, so the headline seems a bit misleading.
The takeaway is: If you pay for any service in a traceable way, you are not anonymous. If you want to be anonymous, consider cash or Monero.