Most utilities, even if ostensibly privately-owned, are profit-limited and rates must be approved by a regulatory board. Some are organized as non-profits (rural water and electric co-ops, etc.) This is in exchange for the local monopoly.

If your local regulators approved the merger and higher rates, your complaint is with them as much as the utility company.

Not saying that some regulators are not basically rubber stamps or even corrupt.

I agree. The issue really is that they are 3 layers removed from where I can make a change. They are all appointed and not elected which means I (and my neighbors) don't have any recourse beyond the general election. IIRC, they are appointed by the governor which makes it even harder to fix (might be the county commissioner, not 100% on how they got their position, just know it was an appointment).

I did (as did others), in fact, write in comments and complaints about the rate increases and buyout. That went unheard.