When computers are not connected in local administrations

Last year, in June, I sold my car. The guy who bought it was French, he came to Italy, we went to the local office of the car registry and made the transaction. They registered that he was exporting the car, took my old plates and threw them away.

Last week I received a letter by the local administration of Lombardy that notifies me that I did not pay the yearly tax for 2008 and that I should do so immediately. At first I thought there might be a problem with the sale I did, but calling the registry (ACI) it was confirmed that my plates have been taken and the car is registered as exported.

What I have to do now is PAY ACI to get a document the proves that I sold my car and fax it to the local administration.

Why can’t they talk to each other? Why doesn’t the local administration check if the car is still in Italy before complaining to me?