I contacted them by e-mail. I couldn't reach them by phone. The e-mail I used to contact them was "rmastatus at buslink.com" (replace at with appropriate symbol). I always received a response very quickly.
When I asked the e-mail support person if I could get the drive replaced with the Lite-On model after explaining what was wrong with my AOpen drive, he said that I should send a note requesting the Lite-On drive as a replacement in the box with the drive, which I did. I also sent all included accessories along with the drive when I RMA'd it.
It took Buslink a rather long time to get me my replacement drive, but it was definitely worth it. My old drive was the AOpen 52x24x52x drive (mine was bad, too), and they sent me a Lite-On LTR-52327S 52x32x52x drive as a replacement!
Edit: Buslink didn't guarantee that they would replace my drive with a Lite-On, but they said that I could ask for it. If you request a Lite-On drive, I'd make sure to mention it in the e-mail as well as in the box; that way, I think you will be more likely to get the Lite-On drive.