No one worth their salt is going to take this case, so you may as well pay it.
The city has no obligation to notify you that a meeting is being held. You need to take the responsibility to find out when it is, put together a quick presentation that covers the facts, and show up. The fact that you expect them to call you and invite you is ridiculous!
The city has every right to put unpaid city bills on your taxes. It happens everywhere for trash, utils, etc. No surprise there.
The city has every right to do estimated billings. If you had educated yourself when you moved in, you would have called and asked for a meter reading at that point. You didn't do so, and now you dispute the numbers. Who's fault is that?
Have you bothered to check and see if you have any leaks or other issues that might have added to your bill?
I'm sorry if this comes across as harsh, but you're not a kid. You should know this stuff.