Slightly OT but:

You never know when someone or a business is just ignoring you. I use the service at http://www.didtheyreadit.com/. It is super cheap. I get a message when my email is opened, read, and what city the person is in when they read it. The person receiving the email has no idea it is being tracked.

Sometimes BA simply never opens the emails I send. But when they do open the email, I always get a response.