Thanks all. Given what purser@AC and Flygirl said, I'm a little surprised the purser did not hand over one of these coupons. The cabin was full as I said and a few things were going wrong other than my chair (examples: 32 pax, nearly all of whom male only a few male amenity kits. Problems with video system, etc.)
I agree that $100 seems a bit light -- particularly on a long-haul evening flight where you basically pay for a J ticket in order to get comfortable enough to sleep. Reading of similar problems on other boards I've seen much higher amounts being mentioned... in US$ too.
I'll eMail the SE desk as suggested.