My apartment's mains voltage rises from 220 V at noon to 245 V at night
Maybe electricity with your poor voltage regulation costs less than with normal and good voltage regulation.
Maybe your electricity uses old transformers that were designed for less power that is used today and should be replaced with more powerful (and more expensive and larger) transformers.
The transformers and underground wiring on my street in Canada worked fine but were replaced when they reached 30 years old. The voltage regulation and reliability are excellent.