New home in AZ, 900 sq ft uninsulated attic

[clc]

What is the name of your state (only U.S. law)? Arizona

Move in day, insulators were there (!), told us to tell superintendent they needed ceiling access at that end of the house to finish the job. That afternoon, I told the super; he shook his head and said "don't worry about it" indicating it was previously insulated on that end with bat insulation. During the next 2 summers, we complained repeatedly to our sales rep and 3 customer service reps about high cooling bills and lack of comfort only to be dismissed as "that's normal, it's Phoenix". Our thermostats were set at 83 degrees, the den and two bedrooms were as high as 90 degrees. Highest bill was $550. Finally, the fifth rep we spoke to cut access into the ceiling, went up and discovered there was no insulation over approx 900 sq ft. (2400 sq ft house). I asked for retribution, the rep sited "right to repair and we don't reiburse bills". They insulated and upgraded the R value from R38 to R44 so that we may "lessen future bills". I pushed for reimbursement of the excessive cooling costs. They agreed only because I brought it to their attention at move in. Now they're using fuzzy math to determine what we should've paid in electric costs for the "cooling" we DID receive and they'll pay the balance minus our base electric costs. Now that the house is insulated, our next bill will show the correct kWh. I think the fair solution would be to compare that bill with a previous bill with similar average daily temps and the % difference is what we are due on the previous cooling bills. Am I being unreasonable? Hindsight Notes: We don't see any insulation certificates posted anywhere, and have been told that you don't need city permits for insulation. We had a general home inspection at 12 mos, but the inspector couldn't access that end of the attic. Thank you very much for any insight, opinions or advice you can give us!!! We appreciate it.What is the name of your state (only U.S. law)?