[Confusedtaxpayer]

I recieved a bill for the first time from Municipal Tax Services which is apparently an agent hired by Waterbury to research where and when taxes were paid. I moved to Waterbury in August 2005 or so. I was living in Hamden. I received a bill from Hamden for my car taxes that year and paid that bill. I changed my registration in August to Waterbury. I paid taxes in Waterbury in 2006, 2007, 2008 and 2009. I just got a bill from Waterbury for 2005 for 396.24 and 196.13 in interest but I explained to them that I paid the tax to Hamden and since this is the first time I have ever seen a bill from Waterbury why should I pay almost 200 in interest? This doesn't seem right. What are my rights? What can I do to get out of this mess? I have good credit and have always been responsible and am concerned on how to handle this. Any advice?