Ihave a similar situation. For the 2008 proprty tax adjustment, the bill was sent to current owner, I told them I only lived there about 13 days in 2008, however, the lady who is a worker of city Ottawa told me,"we only sent bill to the current owner. since it is a small amount of money, it is not worth to find a laywer to deal with that."
City of Ottawa has all information about propery occupation, why they are not resiposible for collecting money from right owner, I could not get they are not doing a right thing but they still have an excuse.
Anyway, find your previous lawyer.