I recently duplicated some awesome boots I bought on ebay, from a seller in China. I have bought from China before, and conversed with the seller easily. When I got my second pair of boots, they were clearly mis-marked -- they were stamped with my correct size, but are about a full size smaller. I emailed the seller:

Me: Hi, I think there was a mistake on the size. I bought the same boots before in gray, size 39/8.5, but these are much smaller and have "8" written on the bottom in pen. Please let me know how to exchange for the right size.

Seller: We don't have a size 8. Those are really an 8.5, but if they are too small, you can send them back for a size 9.

Me: No, the item was marked a size 39, but you had clearly written notes in pen, correcting that it was actually a size 8. Also, you don't sell this item in 9.

Seller: It is a size 8.5! We do not make a size 8... please believe me! if it is too small.what about you send it back to get a refund? or you can choose a style of shoes which have the size 9.

Me: I have the exact same boots in size 8.5. These are not 8.5, no matter what is printed on them. All I want is the correct size 8.5. If I return them, can you make sure I get the right size?

Is there some other wording I can use to communicate what I want? Any suggestions? Anyone write in Chinese? International shipping is expensive, and I don't want to get the wrong size a second time...