Yeah, no way mailfence is that privacy friendly. https://www.hindustantimes.com/cities/mumbai-news/how-cops-c...
The police were able to get a lot of info from mailfence to catch a stupid student who thought using a vpn and mailfence would enable him to send threats easily to the richest man in india. The police got info on how many accounts were from this country, how many of them were active, monitor the mail account for new mails etc..