Upstream change at the neighborhood node causing speed drop, modem cannot speak to neighborhood node. Modem stuck in IPv6 Provisioning Mode

My internet speed is capped at 250Mbps on my gigabit plan. I looked at my modem diagnostic page, and my second OFDM Downstream channel fails to lock, while the first is showing massive correctable codewords. Due to the modem's inability to receive data from the neighborhood node it is locked in to IP Provisioning mode IPv6 Only.  Power levels and signal are good except the downstream ODFM (Channel ID 37 - 690MHz) should be checked for noise due to the large number of correctable code words.  My router is spiking the CPU and bottlenecking the line while it corrects packet errors, causing additional network latency through the gateway.  It needs a a T3/Profile Reset.  How do I get support to do those things?