Proton Mail provided Swiss authorities with payment data for defendtheatlantaforest@protonmail.com — the account linked to Stop Cop City protests in Atlanta. The FBI obtained this information through a Mutual Legal Assistance Treaty request on January 25, 2024, identifying the activist behind the anonymous account through their credit card identifier.
At request of swiss authorities, nothing they could do (companies must follow the law of the country). The guy just needed to have used the free version or a anonymous way of paying and nothing would have been given.