How do I send a complaint to customer service?

[surf22]

Has anyone figured out the process for sending Verizon a customer complaint?  The "Contact Us" portion of the website directs you to call them; I didn't see any email options.  When I called to notify them that the FIOS internet installer missed the four hour window without so much as a courtesy phone call and asked to speak with a supervisor, they transferred my call to a voice mailbox that was full.  How can I speak to a supervisor rather than a dial tone?

Thanks!