Problems with Bluetooth hands-free on the original Tucson Radio

Have our Tucsi *joy* since Thursday. As far as a great car. It is equipped with an original CD radio in double-DIN size. This radio has besides USB and Aux connection also a Bluetooth hands-free device. My mobile phone (Nokia N95) I have already “paired” with the radio and it has also worked so far. Unfortunately I am not understood correctly by my interlocutor. I would be much too quiet and one would hear driving noises. Also w I don’t understand anything. Now my question: Does any of you have experience with this radio and/or with my problem and can help me? Or can someone give me a guide on how to remove the radio without any damage to see if only the cable from the microphone is not plugged in properly? Would really be happy about every tip. Oh yes, what else. Of course I know that I could go to the workshop with the problem, but our responsible dealer (where I did not buy the Fz. by the way) does not enjoy the very best reputation. Thank you in advance for your answers.