I think you've done a good job with the ad. Because you used the word "damaged" it's possible that John misunderstood and interpreted the ad as meaning that the tweeter is inoperable, but I've read it carefully and I understand that's not the case and that the damage is to the dome only and not the tweeter itself. As pointed out, this is not uncommon - many a child has poked at the domes on the 800 series! Either way, his response would annoy me as well and I'd delete it.
If you decide to replace the tweeter, it may be a good idea to purchase an extra trim ring from B&W at the same time - they're only $10. That's the ring that goes around the 5" driver and covers the screws that hold the driver in place. To get into the speaker to change the tweeter you'll need to remove that 5" driver, but to get to the screws holding that driver in you have to remove the trim ring first, and the tabs that hold the trim ring in place can break fairly easily. I learned this the hard way. It's entirely possible that you get your trim ring off no problem, but if you break a tab like I did you'll wish you'd just ordered the $10 trim ring at the same time. Once the trim ring is off, removing the driver is easy and you're then into the speaker no problem.