What happens when you try to update your address? Are you seeing an error message of any kind?
Try another browser to see if that makes a difference.
Rather than editing your current primary address, add the new address separately; then make the new address your Primary address. Then delete the old address.
That should work, assuming your new address is in the database that eBay uses to check those things. If you are moving to a new development on a brand new street, the database may not have been updated yet.
