Denied boarding on my China Eastern flight to Bangkok Thailand [closed]

I was to fly to Bangkok, Thailand, via Nanjing, China, on a China Eastern flight from Vancouver. However since I am traveling using a Canadian Refugee travel document I was denied boarding by the agents saying that I need a Chinese transit visa. My transit time in Nanjing was for 7 and a half hours. What the airline right to deny me boarding? What options do I have? Thanks.