After contacting the customer service department, and in the absence of a satisfactory response within 1 month of the written complaint, the customer may refer the matter to the Tourism and Travel Ombudsman (Médiateur du Tourisme et du Voyage).
contact details are given below:

Postal address: Médiation Tourisme et Voyage
BP 80 303 75 823
Paris Cedex 17

Website: www.mtv.travel