How to deal with this situation?

We bought a new home last September. The first water bill for the period 05/19/2015 to 11/16/2015 showed a usage of zero and a flat unit rate of $60. We paid this. A couple weeks ago a random person showed up at my door claiming to be the "town water manager" wanting to enter my home and look around the basement. I denied him because he had no ID, vehicle, or uniform and looked generally un-kept. Another water bill arrived in the mail along with a letter. The letter says this water manager would like to do a "turn on/off" and that a $25 fee will be added to the next bill. The bill is for $289.84. The same flat unit rate from the last bill we paid of $60 is there plus the $25 fee and the rest is over usage. This document claims 63,000 gallons in water over usage in the 6 month period between 11/17/2015 and 5/26/2016. What to do? Using conservative estimates for our brand new energy star appliances we calculate our actual usage around 900 gallons.