How do I find out who does the billing/utilities for an apartment complex?

Just recently moved out of an apartment in Houston, Clear Lake area.

I received a final statement with some outrageous "per day" charges for utilities, sewage, trash collection, pest control, etc. I've never heard of "per day" charges on utilities and the rental office will not give me the name of the utility company or the billing company. Electric is separate and I've already settled with them and paid my final bill.

$59 dollars for gas. We don't have gas, except in the laundry room, which is contracted out to a separate company. That alone is more than my entire utility bill has been since I've lived there. $19 for sewage and trash. Pest control is part of the rent payment, and we had gone months without pest control. There's a lot of other charges that don't make sense. I also paid $750 in deposits, and they are saying they have $200 in deposits for me. (Going to the bank for that, it was several years ago)

They have done some sketchy things with utilities in the past. I've sent 3 emails asking for the name and contact information of both the billing company and the utilities and they keep putting me off.

Pretty sure the water is Clear Lake Water, but not sure.