There's a place on your Create your listing page where you block locations, it says "exclude postage locations" but you have to set that up - so you could say for instance if you didn't want to deal with anyone in a certain part of the world. You can also block certain bidders (you might do that if you've had trouble with a transaction). However both of these actions have to be set up so I am not sure what might have happened here. Rather than using the edit button, go to your item listing and click the little drop down arrow on the far right and select the Revise option, which will bring up your original listing (this is quite different from the options on the Edit button). If you look at what you listed, down near the bottom you will see the exclusions and you should be able to see if that's activated. If so you can change it back. If not then I suggest you contact eBay via the Contact Us button (top right) - I have found they are very good at getting back to you and sorting problems out. Good luck - I hope this works.