Hi Amanda,
I'm really not sure what you are selling as your shop announcement simply states "International Customers please contact me if you are interested in an item"
If you really think about it, everyone on Etsy is an 'international customer' depending on where the shop and buyer are located.
When it comes to refunds, you only refund if the purchase price is under $75 and for store credit only? I find that a bit odd myself. If you aren't willing to refund on an item, a buyer simply needs to file a claim through their credit card company to get their money back.
Your descriptions are really lacking in details. If you are selling clothing I'd suggest that you provide actual measurements rather than 'size small'. What size is size small? I've got clothes in my closet from various manufacturers that run the gamut from small to large.
Saying 'this sweater is really cute' really doesn't tell me anything about the sweater. What's it made of? What are the measurements? What colour is it?
Remember too that if you don't have shipping listed for a specific country, that buyers from that country simply don't see what you are offering unless they go digging. So if you are going to ship outside of your own country, I'd suggest that you do the investigation into the postal rates and set them up accordingly.