So it turned out that you need to press "request combined shipping" and
wait for seller confirmation in order to buy successfully. This looks
like a ebay bug.
Just changed to Poland and now the coutnry in profile shows correctly.
However the issue remains the same. Maybe need to wait for some kind of
ebay cache to be updated.
I have only one adress in settings and it is Poland with correct postal
code. I removed the dash symbol from post code just now, but in cart it
still says 63-400. I have noticed that sometimes it takes some time for
it to be updated everywhere in eba...
