Why do some sellers use multiple currencies and addresses for one transaction?

[charmcd]

Why did a seller sell me an item in GBP, ship it from Great Britain but when I received the parcel in New Zealand the return address on the parcel was actually an Auckland address. 

Then to complicate matters even more I was told to return the misrepresented item to China.  After a maddening number of emails, the seller sent me a PayPal refund in USD for the return shipping. 

I then had the hassle of opening a PayPal account even though I had purchased with a credit card.  Is all of this quite normal on eBay?  Needless to say, I never received my refund for the item and the seller no longer responds to my emails.  eBay can not help me.