There are various ways to deal with problematic users in Joomla!, but the recommendation is not to delete the account. Instead, block the user from logging in. This serves a temporary suspension that can subsequently be rolled back when and if necessary. If you require users to authenticate their accounts by email, it also prevents the user from simply re-creating an account using the same email address.
To block users from the Joomla! back-end, head to Users > Manage. A list of currently registered users will be displayed on screen.
Check the box next to the user you wish to ban and click the Block button. The user won’t be able to log in to the site now.
Use the Unblock button to restore user access.
If you notice any problems or if you need any help, please open a new support ticket from your HostPapa Dashboard. More details on how to open a support ticket can be found here.