I've already answered this and think you've let most of any claim you might have had for overpayment expire.
Here's what you do if you want to make a claim against the city: Check the city's website for an "administrative claim." If you can't find it, call the city attorney's office to ask how to download one. Fill it out and submit it to see if the city will pay for your sewer hookup. Submit whatever photos and bills show the cost and why you think they should pay for this. I'm guessing they won't, but it's pretty standard for cities to deny administrative claims. Once they deny your claim you can sue them in court if you want.
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