Iphone 6 no connect to wifi and 4G. Restored all settings but still doesn't work

Just today morning, while i was in Hong Kong, wifi and 4G was working without any problems. But when i cross the border to China, its just stopped working. Its show 4G, but no have internet connection. The same story with wifi. iPad and Mac don't have any problem with wifi connection. I restore all settings, shut down iPhone, still didn't changed anything. Does any one know what should i do?