Negligence/Unfairness

So recently we discovered that we have been paying our neighbour's municipality bill for nearly 8months due to negligence and an error made by the engineer (P.Farmer)as he swoped the property numbers and water meter numbers. Our account increased with more than R800 and our bill is nearly R2500 for this month. I did send a mail to Mr. Danny Le Roux who is the principal engineering technician, as this is unfair towards me the client and new home owner but he informed me the financial department made a correction and we need to pay the arrears amount as we used the water, but how can i be penalized for an error/negligence from the engineer, if attention to detail and accuracy took place this would not have happen. We already live in a tough financial economy and know i am liable for an arrears payment. I was also informed i can make arrangements to pay it off in 3 months, to receive less electricity units, no way. No accountability is taken from the municipality, so it's fine to make mistakes and be negligent, me the client just needs to pay whatever comes your way.