How can buy from eBay Australia?

I'm in UK. I tried to buy Mobile phones / iphones from eBay Australia but all phone sellers mention these words with their listing. "May not post to United Kingdom". I have sent a couple of emails but did not receive any reply.
Is there any one who can explain me the reason please?

If they don't answer, the answer is no.
Only those who say they'll ship overseas will do so.