How to contact Comcast?

I have already tried: going to the local office (twice), calling (I don't remember how many times but it was multiple times), using the online chat.  None of those mechanisms work.  I would love to mail them a real letter because I've heard advice that this would give me better legal protection than phone calls or online chat.  But guess what: Comcast's Conctact Us web page gives 6 ways to contact Comcast but none of them is a physical mailing address.  The bill that they sent me doesn't include a mailing address than then one for mailing payments (there's also an address of the local office which I guess I could use to send a letter to).  So, my guess is that Comcast also thinks that mail would give their customers a better legal standing and they intentionally do not provide it.

Instead of mailing a letter, I tried something else.  The same Contact Us page has a way to send feedback to Rick Germano.  Who is Rick Germano?  Here's what the Six Ways to Get Help page says:
"Hi, I’m Rick Germano, head of Customer Operations at Comcast."  Here's a picture of Rick:

He looks like a nice fellow, so I thought that it was worth a try.  Here's the letter I wrote to Rick:

My account number with Comcast is XXXXXXXXXX.  On 5/29/2008 I visited the Comcast office at 1400 Terra Bella Ste D, Mountain View, CA 94043.  I returned my equipment and requested to cancel all my services (I would be happy to email or fax a copy of that receipt of the equipment return).  In the following months, Comcast has been billing me for services I no longer receive and for rental of equipment I no longer have.  Whenever I receive a new monthly bill I am contacting the customer service.  I was first calling Comcast and I visited the same office where I originally returned the equipment.  More recently I have been using the online chat on the Comcast web site to have some kind of record of talking to your customer service.  I used the chat on 7/25/2008 with Melinda (chat id 28370746), on 8/25/2008 with Brenda (chat id 29465037), on 9/23/2008 with Marco and on 9/25/2008 with Zhenaida.  Both Melinda and Brenda acknowledged that this a problem with the Comcast records and they both said that they will make sure that I will stop receiving future bills and they both said that I would receive a refund of $142.29 in 4-6 weeks.  Not only I haven't received any refund but I still keep getting bills from you.  The most recent one arrived today and adds false charges for 9/23/2008-10/22/2008 to what it assumes I already owe.  The other two analysts I talked to (Marco and Zhenaida) were not able to help me because "the program we use to access your account information is currently being upgraded to serve you better".

The situation is completely ridiculous.  Please fix this problem immediately and send me a confirmation that this issue has been resolved and send me my refund.  My address is:

XXXXXXXXXXX

Palo Alto, CA 94303

Sincerely,

Michal Cierniak

I sent this letter on the evening of 9/27/2008 and immediately got this automated response:

From: Comcast ECARE

Subject: Thank You for Contacting Rick Germano! Your Message Has Been Received (XXXXXX)

To: cierniakmail-XXXXX@yahoo.com

Date: Saturday, September 27, 2008, 10:32 PM

Thank you for taking the time to share your feedback regarding your

experience with Comcast.  Your feedback will assist us in our efforts to

continually improve the Customer experience.   To respond as quickly as

possible, I have asked members of my leadership team to join me in 

addressing all "Ask Rick" messages.

Thank you for being a Comcast Customer.

Regards,

Rick Germano,

Senior Vice President of Customer Operations

This is an auto reply message letting you know that we've received your

e mail, so please do not reply to this message

No response yet but I'm hopeful that Rick or his staff will be able to help me.