Can customers in Plesk remove/cancel their own accounts?
Customers cannot remove/cancel their accounts via Plesk.
It usually is done through a billing system, where customers can actually control their payments and such.
For example, WHMCS.
To implement functionality in Plesk, share the idea on our UserVoice portal: https://plesk.uservoice.com/
Top-ranked suggestions are likely to be included in newer versions of Plesk.