In case you are in trouble with the software or hardware of your Kindle, you may want to contact Amazon directly via e-mail or phone.
E-Mail:
kindle-cs-support@amazon.com
The following phone numbers proved to be useful as well:
* 1-866-321-8851 (if you are calling from within the US)
* 1-206-266-0927 (if you are calling from outside the US)