Decide if you actually want to write to the headquarters of Comcast Cable. Comcast does not list their corporate information in any of its customer contact pages on their website, so if you are writing a letter (positive or negative) about your cable service, you should write to the nearest Comcast service provider or email Comcast through their customer support website. The Comcast headquarters is located at One Comcast Center, Philadelphia, PA, 19103, but unless you are a shareholder looking for information or know someone important at Comcast personally, you are unlikely to get a response.
Write your email or letter. Clearly and concisely state your reason for writing your letter. Make sure to be polite, even if you are extremely upset. Using vulgar language may cause your letter to be discarded. A library book or Web site with tips on business writing can also make your letter stronger.
Send your letter. If you must send your customer service-related letter to Comcast's corporate headquarters, do so, but do not expect a response. If you choose to go this route, you should also send a copy of your letter to the nearest customer service center.