Formal written letter (not e-mail) to CEO
I had a billing problem and emailed the CEO after a frustrating 2 hour phone call when I was passed from pillar to post. My email was at 12:00pm on a Saturday - I had an email back from him at 7:00pm and a phone call on Monday from someone who promised to fix the problem - it was fixed. I was left feeling that if it hadn't been the CEO would want to be informed. I was most impressed.
Give it a try.