The user can always delete the user account at any time. The user account, and all the content related to it, is immediately deleted completely and irreversibly when logged in user completes the account deletion.
The user account, and all the content related to it, can be deleted at any time by the server maintenance. By design for the security, the server administration cannot warn the account owner about the deletion of the user account. Due to misuse, the account will be deleted. Inactive accounts will be eventually deleted.
Logged in user can, among the other account management functions, request the account information as a json file. File include everything that is stored in the database from that user account. For the security, it does not contain the user name, email or password information.
The service has email verification. You need to have working email address to be able to use the service. Without completing the first email verification, usage of the account is not possible. Non verified accounts will be deleted after a one day, 24 hours.