Sorry to hear that. A friend in Denver just had this issue in the apartment
he moved into last week. He bought two
https://www.amazon.com/dp/B015H0A3FO
meters which made it quite clear.

At my advice he used the words "Open Neutral" and "Fire Hazard"
on the ticket. He also unplugged everything not run by UPS &
logged UPS input voltage every which made it quite clear.

The electrician took one look and called the PoCo. They
responded ~4 hours later. They soon found poorly torqued
neutrals in the 14 meter panel/ main disconnect.

The two phases then stayed equal and stable.

On your losses, check your homeowner's insurance coverage.
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