Volume problem BT headset

[ocyberbum]

Hello I'm having a problem with a Bluetooth headset HS WLS465, it's designed for a motorcycle helmet. The problem is when I'm listing to music the volume stays at the level I set it using the volume buttons on the headset but when I make a call the volume goes up real high and down to low while I'm riding. I didnt have any volume control software so I Google around and found an app called A2DP volume which don't seem to do anything either. I contacted the manufacturer of the headset and they say that my phone is doing it and there product just amplifies the source. It only happens on Ph calls and when I'm riding it acts like its adjusting the volume based on the noise in my helmet or something with the GPS is adjusting it as I speed up. Is there anything I can do to adjust or turn off what is causing this.. any ideas would be appreciated