I haven't seen this thread with the other customer having an issue and can't speak about the process followed. Normally, your first line of engagement with any issue should be your dealer. If you contacted your dealer and received poor support, well...it is Vivids fault I suppose for working with a poor dealer.
As a Vivid dealer, I will say that they were incredibly responsive. I had a customer who called me to tell me that they "blew a driver" in their Oval B1 Decades because there was a distinct rattle.
Laurence Dickey directly offered me advice on how to evaluate the speaker on site and to see how we could get this resolved. As it turns out, the driver was fine. There was a panel a few feet away that was vibrating and the reflection of the sound made it seem like it was coming from the back of the Vivids.
If you have purchased them used, you would need to go straight to Vivid. But, even then, I directly supported a repair on a used pair of speakers handling the financial transaction which was brought to me by my rep.
The only thing I see as an issue with these speakers is that the drivers are incredibly delicate and are easy to damage during setup or re-packing. I have not had an actual issue with speaker I have sold.