paying for some one elses water 10 years later

WE sold our house in February 2015 after living there for almost 10 years and when we received our final water bill we found that the previous owner a Mr Luff had not settled his bill and it had been added on to ours. After numerous phone calls and visits to the CT Municipal office we have reached a dead end. What I would like to know is how someone can sell their house (to Us) and still owe the City R3400. and get clearance and then we sold the house and they the City took this persons water bill off our final settlement payment, we are desperate to get this money back as afterall it was a Mr luff who owed the city the money and even tho they acknowledged this, the still wont refund us. Is this is their attitude we will need to place our X somewhere else in the municipal elections coming up