Hi Petra,
I work for Ford in transmission electronics, and my good friend works at Visteon (our stereo supplier) in speaker design. He know's all of the people responsible for the systems, and would be very interested to hear about the problem you described. Could you please let me know the year, make and model of your vehicle, and what type of stereo (tape w/ cd, 6 disk changer, etc..), and I'll forward on the information to him. We sure don't want to lose any more valuable customers like you due to bad product and service, and appreciate any feedback. Please email me at wwatts2@ford.com and include the text from your original message about all the incidents.

Thanks again, and very sorry for your experience.
Billion