Just received my B&W 802's: One tweeter doesn't work - HELP!

After testing many new speakers (Magico A3, B&W 801 D4, Wilson Sasha DAW, others) I realized I really, really just liked the tonal balance of my current B&W 803 D2's. Because of this, I sought out a pair of used 802 D2's, as an upgrade that would have the most similar tonal balance. I found a pair of "mint condition" used B&W 802 D2's for sale online, from a very well-reviewed retail shop. After receiving them, I was actually surprised that the speakers were truly, in fact, in mint condition. Everything about them seemed brand new. However, that was until I tried them for the first time and found that one tweeter produces no sound at all. I triple checked all phase connections, and tried removing the jumpers (the mid-range cut out as expected when I removed the jumpers). My questions: 1) Can anyone tell me the most likely cause of a tweeter failing totally where it produces no sound at all, and yet the speaker and tweeter itself visually appears to be in pristine condition? Loose connection internally? Blown crossover and/or tweeter unit? 2) Further to my first question, how would this issue be addressed? 3) How would most reputable retailers respond in this scenario? I've sent the retailer an email (they are closed for today) indicating the issue, along with photos of my connections to prove correct phase, etc, and also a short video showing a recording in front of the speaker with it's tweeter working properly, and moving to the other speaker where you can clearly hear the tweeter is not making any sound. 4) Would B&W help at all, considering these are older speakers and the fact that I purchased used? 5) Any advice? It's frustrating, because I can tell from what I've heard that these speakers were everything I was hoping for. Less one working tweeter. Thanks....