Astronomical Electric Bill

Yes, another one of these posts. I live in a 2 bedroom upper floor of a 1930s duplex. Insulation and windows are old and not efficient. Our electric bill this month was $430 (2420kWh at 0.14¢/kWh plus Centerpoint Delivery Charges). The highest it’s ever been by a long shot.

I might be okay with this if we were living comfortably in this heat, but instead our AC is running all day and it doesn’t get below 80/81° inside until the evening. Our thermostat is set to 76°, though it rarely ever makes it there. Seems like a slap in the face to be paying more just to be hot. I’ve notified the landlord of the issue in writing, but he has taken no action. Is there anything else to be done?