The simplest way to mitigate under (and over) voltage would be to install an under/over relay device, many are available on Lazada etc.
These cut the power when the voltage goes outside the set range, of course you then have no power to whatever it is protecting.
Alternatively, voltage regulators are available (both small and large) which regulate your voltage, at least to an extent.
How low is your voltage going? Do you have logs you can show PEA? You're probably not going to get compensation but you might get them to fix (or at least improve) it.
Or, do like we and others have done and install solar with a battery for backup, say farewell to any other power cuts with the bonus of reduced power bills.