出口信用问题

塞尔维亚这个国家信用怎么样！我们有一票货出口到塞尔维亚，但是港口是克罗地亚的里耶卡！第一次合作，出货前30%货款，剩下70%见提单copy件付！请问这样有风险吗？客户的这段话是什么意思呢，如何才能控制我们的货权？ however, we he another suggestion for terms of payment: we could pay 30% t/t in advance, without bank guarantee. you arrange transport with your transport company and the goods stay in your ownership until we pay the 70% balance. after we pay the whole amount, then you send us the original documents.