Since I upgraded to the 500Mbit/s and the Fritz!Box 6690 Cable modem, by connection has gone from bad to absolutely terrible. The only connection I can get to work at all is via IPv6 utilizing DS Lite for IPv4, but it barely works. I will get a tiny spurt of internet for a second, then nothing. My Fritz!Box shows I have a connection, but it not stable and extremely slow. I've attempted to switch the connection over to IPv4 native, but it will not connect. Below I've attached some data from the router and a connection test to google.com. This shows a packet loss of over 65% with an average ping of over 50ms.
Please help! I've attempted to call the hotline numerous times, but my German is not good enough to understand the menu prompts.