Chances are, you might have an issue with the mobile. You can check if the headset is working well using a different mobile. If the issue still presist with an alternate device proceed with replacement as per policy
4.1 How to unpair from the mobile
1. Tap and hold the Bluetooth icon on your mobile
2. Tap on the Noise Buds VS303
3. Click on Remove / Forget Noise Buds VS303
4.2 Pairing with a new device
Tap and hold the Bluetooth icon on your mobile
Turn ON the Bluetooth
Make sure your mobile and the Bluetooth Earphones are within 1-meter range
Go to add devices in your bluetooth settings
Search and Select Noise Buds VS303
Tap the Pair option on the pop-up