Hello Cynthia de boer,
I am really sorry for the delay of this reply as it is a public holiday for us here.
To fix this in the future, you should install this plugin
plg_easydiscuss_users.zip in your site, you can download from
http://stackideas.com/downloads/plugins (All EasyDiscuss Plugins).
*This plugin is responsible to delete user's related records such as question post, reply and etc.
Then go to your
backend > EasyDiscuss > Setting > general > Maintenance > Owner for orphaned items - set your Super admin ID here
if you need further assistance, please provide us with your Joomla backend and FTP access so we can help you configure with this.