Customisable notifications cannot be removed

I noticed in the last update, the ability to have customisable notifications has been introduced. I get a notification in the notification shade saying "Service is running" but I don't want this to show.

I've gone into notification settings in Kustom and clicked on Disable, and then into my Note 9 battery settings to place Kustom into "Apps not optimised", but I am still getting the same message in the notification shade. And instead of Disable in the Notification Mode section, it stays on Automatic.

Please can you fix this as I really don't want the "Service is running" notification in the notification shade and the Kustom app icon showing constantly in the notification panel at the top of my screen.