I don't know if I want some flight voucher, I would rather be refunded my miles. To me it's not just about a non-functioning seat. I had an 12 hour layover in NYC after my flight that I had planned on going into the city. My flight left at 11:30pm so I had planned on sleeping on the flight. This is one of the few times I kind of feel justified in asking not only for what I paid back, but something extra to say sorry for my negative experience.
I feel kind of upset that there is no one directly you can talk to in person when you not only experience like this. I think it is poor customer service to tell someone the only way they can contact someone about an issue is to write an email.
If they knew ahead of time that a seat was broken, they shouldn't have upgraded to fill the entire cabin.