Hong Kong passport holder transit flight in China

I booked the ticket to fly from Amsterdam to Hongkong and transit the flight in Xiamen, I have Hong kong passport and living here with resident permit.The airline advised that I need to have "A Mainland Travel Permit for Hong Kong and Macao Residents' card which I do not have and it needs to apply in Hong Kong. As I know the Chinese travel visa are not for Hong Kong citizen to apply. I would like to ask the Chinese embassy here but they are just so difficult to reach. :( Do you have any idea which kind of document that I can apply?

thanks!