where do i file a complaint

In 2015, I purchased a 2012 Ford Focus. Since then I have received 3 recalls.
The transmission issue resulted in my car breaking down many miles from
home. This however is not the biggest issue at present. In the last 2 months I
have had loud popping coming out of the speakers, whether the car was on or
not. I called the corporate office and they indicated that they were not recalling
the radio. I explained to the customer service rep that the popping is painful on
the ears which is extremely dangerous at it startled me resulting in a close call
accident. I refuse to believe that this is something they can't fix. When I bought
the car, I was unaware of the defects and that the radio would eventually quit
working. The customer rep suggested that I write a letter to the corporate office.
I fully intend to exercise my rights. This is crazy!! If anyone would care to write
and send a letter, let me know and I will provide address. WE have to hold them
accountable!