Talk about pro-active customer service. This is the kind of thing that makes a customer for life:

Because you may not have been able to playback one of your rentals or purchases in HD quality, we have issued you a one-time Amazon Instant Video credit of $1 for each of the HD movies and TV episodes you have purchased from us for a total amount of $32. 

I really have no idea why they would do this, but I'm not going to complain!