One possibility is that there's an issue with the Bluetooth connection between your phone and the earbuds. You could try unpairing and repairing the devices to see if that helps. Make sure to completely forget the device on your phone before attempting to pair it again.
Another possibility is that there's an issue with the audio settings on your phone. Make sure that the audio output is set to your earbuds and not the phone's internal speaker.
If neither of these solutions work, it's possible that there's an issue with your phone's Bluetooth hardware. You could try resetting your phone's network settings or contacting your phone's manufacturer for further assistance.
I hope that one of these solutions works for you and that you're able to enjoy your Razer Hammerhead Wireless X earbuds with your phone.