This afternoon I received an email from BBB, saying that my complaint about TLC "has been updated with a response from the business."
Going to the BBB site, I see:
Date Case Opened: 2/20/08 (a Wednesday)
Sent On (to TLC): 02/22/2008 (a Friday)
Complaint Sent Via: Mail
So the BBB takes 2 days to process a complaint, then they send it by U.S. mail to the business. That could be a part of the reason that nothing seems to happen right away when you complain to BBB.
The BBB website indicates that TLC has issued me a ticket (which they did this morning), so TLC's reply was entered into the BBB website on the same day.