Telephone sounds like under water

[foggy595]

Hi
The bluetooth telephone on my Z4 E89 is perfect in hearing someone talking to me but it sounds like I am talking from under water to the person on the other end.
It has been to my local dealer who replaced the microphone to no effect. It has been back in today and they have tried to re programme the unit but the re programme has failed several times.
The dealer now says it needs a new head unit but cannot guarantee it will solve it. £400 for a new head unit with no guarantee of resolution is not a risk I can afford to take.
Has anyone had a similar problem and what did you do o resolve it?

Thank you

Richard.

[djstan]

Can you sync a different phone to the car and see if the problem still occurs? That will help you pinpoint whether it's the phone or the car at least...