Monster Cable Products iCarPlay Wireless 1000 destroyed my car electronic system. Kept product but gave no refund. Brisbane, California

Monster Cable Products is a very unethical company.  If you read on Yelp, there are other consumers who have been cheated and scammed by this company. 
I purchased an iCarPlay Wireless 1000 in June which destroyed the electronic system of my vehicle.  I filed a claim and of course Monster told me they do not feel their product ruined my electronics.  I have 2 mechanics telling me it is the likely culprit. Furthermore, they tell me they destroyed my iCarPlay Wireless 1000 and will send me a check for the amount of the product.

I appealed their decision regarding the iCarPlay Wireless 1000 not destroying my car.  Going on 3 months no answer.  It is now 7 months and they still have not sent me a check for the destroyed iCarPlay Wireless 1000. I emailed them and this is what they told me.
"On Tue, Dec 18, 2012 at 3:41 PM, Customer Support <customersupport@monsterproducts.com> wrote:
The Accounts Payable department does record of the generated RMA# and all of the information that was submitted however they do not have record of the check being processed and mailed out to you. We will expedite this as quick as possible and we will have it overnighted to you.  We will forward you the tracking information as soon as the check is processed which should be within the  2-4 days. Thank you for your patience and once again we do apologize for the timeline for you to get
the refunded amount of the transmitter.


Thank you

AMD Customer Technical Services
Monster Cable Products, Inc.
455 Valley DriveBrisbane, CA  94005
(877)800-8989"

That email was December 18 and it is now January 13 almost 1 month and that "overnighted" check still has not arrived.  I have since emailed them 3 times and have no response.  Their phone support just hangs up after extended holds.  This company is a fraud and I am contacting the California attorney general. This company is terrible.