Make sure your headset and the mobile are within 10 meters range.
If customer streams the music Online make sure the internet connection is stable
Select the streaming quality to the maximum for better sound quality, If this doesn't help proceed with replacement as per policy
7.1 Check for the streaming quality
On mobile tap on the Music player
Tap Streaming Quality
Select HD or the High
1. Distortion on Music or calling : calling : Normal or Online : Normal call : Network issue
Wi-Fi calling off if still issue persist go for Reset and if not resolved go for RPU.
Music Online : Change network/ Wi-Fi and check still issue persist check streaming quality and Reset Post that if issue persist go for RPU.