Bests & Worsts Reviews from Amazon

I bought two of these to replace my two $25 Encore routers in my home. After flashing the latest firmware (AC15 Firmware V15.03.05.18_EN), you can now select AP (access point) mode. I thought great, just what I wanted an AP instead of a router. However, I finally realized that the entire wireless network wasn't using IPv6 but falling back to IPv4. I'm running all my traffic through a Linux server which allows me to monitor my network interfaces. I can see wireless devices ask DHCP for an IPv6 lease and a response is sent but they are not receiving the response. They ask again and again never seeing the response. Wifi devices aren't seeing the reply for neighbor-solicitation inquiries either. As a test, I re-connected one of my old cheap Encore routers (in AP mode also) and wireless IPv6 traffic works fine. I emailed Tenda support 5 days ago and haven't received a reply. Not even a response that says "Yes, we've received your email". I chose email support over telephone support because the phone number listed on their website is an international number. I can't afford the expense of a long-distance call to be waiting in someone's queue with a recording saying "Thank you for your patience. Your call is very important to us". I really like this router and was hoping Tenda support would produce a firmware update that would fix the IPv6 issues. However I'm doubtful about that now seeing how slow/non-existent their support is. UPDATE: Here some jaw dropping information. I got in to the AC15 through telnet using a KNOWN BACKDOOR which means if I'm on your network, I can own your router! This router is running an ancient version of Linux (Linux Tenda 2.6.36.4brcmarm) and has absolutely no knowledge of IPv6. There is no /proc/sys/net/ipv6 directory! This the same for both AP mode and router mode.