Alatalia Airlines

I would like to make a complaint against Alatalia Airlines. They lost my luggage when I was traveling NYC to Naples,Italy. I had no luggage for 5 full days while in Italy. When I spoke with them, they said my luggage was lost somewhere in Paris and I would get it ASAP. 5 days went by without luggage. They said to buy what I needed and they would reimburse. I wrote 3 letters, giving them detailed receits...NO RESPONSE!!!! Never got anything, no reimbursement, no response. The letter I sent were certified, so I know they received them. My name is Tracy Carlo and I traveled Aug/Sep of this year!