Require Background Notification service Modification for one MusicPlayer App

I have coded Service named "MusicService" and in that I have code of notification channel for access media from background but I can't get that notification while audio is playing.
I've attached image of notification channel requires.
Also make sure code will work on lock screen also.
it's very small task you've to code remotely from my laptop.
and my budget is 1200INR so don't bid above that.