Hello Henry,
Thanks for reaching out to us.
1. At this point there is no real option to recover deleted tickets. There is no trash for the tickets, when they are deleted, then they are removed from the database.
The only way to recover them is to roll back to a database backup that still contains the tickets.
2. The way to remove the delete button from all the tickets: this can potentially be done with jquery that runs after page load and removed those tags, maybe with this function.
A very rough way of going about this would be something like:
function aguseo_remove_delete() {
echo "<script id='aguseo'>
( function( $ ) {
$( '.trash' ).remove();
} )( jQuery );
</script>";
}
add_action('admin_footer', 'aguseo_remove_delete');
You would need to refine that so it only runs on the needed pages.
Hope this helps.
Cheers,
Andras