Entry refused by Turkish customs

Hi,
I'm a french traveller, I'm living in Sofia (Bulgaria), and I wanted to visit a friend to Shangai during 6days. My flight to go to Shangai was : Sofia - Istanbul - Shangai. Turkisk customs has refused to me to take my flight to Shangai as I had no visa. Is that normal ? I wanted to use the 144hrs free transit with the third country as Turkei. Is it possible to request a refund of the ticket to my airline ?
Thank you