I deal with a lot of customer all over the world, but some of the customer don't want to pay the sample charge even freight cost, we send them the sample free ,but we can't get back any news ever since then . I heard that they just want samples. They have no idea how expensive the cost for samples.
Have you ever have same bad experience ? How are you gonna to do with them ?
send the sample to buyers when you receive their money or remittance.