到这步了,你能做的是让他意识到他有义务必须要付孩子抚养费。再说清楚一些,你如过要靠打官司上庭就算在花了很多律师费法庭判他必须付孩子抚养费的情况下(有可能你就算上庭啦也达不到这结果),如过之后他就是还是实际不付或抵赖,then you almost still can do nothing to him to get money, because no one or there is no system to enforce him to pay if he is in China.
you absolutely need to get a lawyer, at least get consultation from lawyer, 先花几百美金for initial or detailed consultation is very necessary for you.