I thought Proton was a confidentiality / privacy oriented thing. How do they even know who owns the accounts?
You can disable an account without knowing who owns it, although they do have credit card/payment information now, and I don't think new accounts get encryption services unless they pay. That said, if your inbox is encrypted, protonmail does so on the client side with a second password. They can maybe delete the account, but proton mail doesn't know what the encrypted data is. What happens to new emails sent to a dis…
source? Their compare plans page specifically lists "End-to-end encryption" as a feature for their free plan.