Blueant Z9i and 8830

I can pair my Blueant Z9i bluetooth headset to my Blackberry 8830. But, when I answer or place a call, the volume is low. I max out the Z9i volume, but can barely hear. I notice that the volume bar on the 8830 is at about 33%, but cannot be adjusted. My other Bluetooth headsets let me adjust the phone volume. This one won't! Is it compatible with the 8830? Is this one defective? Also, I turned the "echo" and automatic volume limiter off on the phone, as instructed by Blueant. But, neither of these helped. No matter what volume I set the phone, the Blueant sets it at one-third, and won't let me adjust it. Any suggestions? Thanks!