my friend, i am speechless to start with but had a situation much like your own.

One month i got a bill that was just "impossible" even if i kept every light on and had my stove running for 744 hours along with every known device in my home i could never reach that amount. In the end i got an appointment with some head and explained to him the situation and we got it resolved that is after i was without power for some time and faced other charges and penalties.

In your case i would let people do a COC on your mains "both electrical water and sewage" Take photos of the land in question and find a good lawyer to make a case against the municipality for making fraudulent demands to pay utilities. The judge will make a ruling and if you are lucky it will be a standing ruling. My personal experience that municipalities do not want to listen to your side of the story but once it goes to court they tend to react because the charges can result in other criminal charges and they find themselves faced with the letter of the law. I am sure once you force them to take a physical look and show the Judge the truth they will and will be legally forced to consider alternatives.

Just make sure your property tax is up to date. That is important because it is the one thing you cannot get away from.

I hope this helps, best of luck to you.