[Sephiroth]

Yes - the codewords, particularly uncorrectable, lie at the core of poor performance where they are growing from one day to the next.

The causes can only usually be found by Network Engineers unless it's a faulty modem.

The TV is in a common path with the broadband but on a different frequency. The V+ box glitching is evidence of something happening on the circuit in the common path. That's the line from your cabinet.

Any joy with someone at VM taking ownership? Real ownership, I mean.