National Water Power- GREYSTAR AKA NPW- Willow Lake Apartments Over billing water utility Katy Texas

I moved in Oct 12 had a water bill of 43.00 APPX, "National Water & Power" sends the bill.  First bill I called NWP and they said that the meter was broken but after 3 phone calls it turn out they were giving me an estimate but regardless of that they started an investigation.  They asked GREYSTAR do to a bucket test but property managers said that they did not know anything about that and that NWP HANDLES THE BILLING. 

I have a meter and I know is working just fine. According to NWP they were supposed to be able to read the meters and since I called now Greystar is saying that is "allocate" so TCQE is ok with the allocation.  I called Greystar's headquearters and the manager said that they were giving me the run around but there was nothing that she can do to help me.  

I'm not home most of the time, I don't have a washing machine, use paper plates and we are only 2 in a 500 sf apartment.  When I signed the lease they never say to me that it was everybody's average. I understood from the manager that it was an estimate of my OWN usage or close to my condition.  Previous tenant had a washing machine and it was always home.

I keep track of my usage and always pay on time.  I called TCQE and they said that I should not get a number with the estimate but still nothing happen, NWP is still running and investigation since March.  Now WHY I AM PAYING TWO TO THREE TIME'S WHAT I USE IN A MONTH!!! IF SOMEONE WILL HELP ME STOP THIS COMPANY FROM OVERBILLING, PLEASE HELP ME.

If I take them to court what is the right approach???