Using command blocks to stop audio playback
The play command is used to stop Media it is playing. When executed, all media will be stopped for a player (with exception for Regions and Speakers).
You can also add an id to the end, and only the sound with that ID will be stopped. The code follows the following format:
/openaudio stop <selector> [id]
<selector> is the only required argument, [id] can be left out*
And to stop the sound with the id
for the player
/openaudio stop Mindgamesnl chill_station