eBay 20% VAT added buying from EU

I just bought some hi-fi gear on eBay from a Greek seller who is a business seller. He created the listing especially for me with price of £100. eBay added 20% VAT at the checkout. I thought that below £135 was VAT exempt?

Anyway, even if VAT is liable, how will Royal Mail that I have already paid 20% VAT to HMRC through eBay? I'm concerned about paying import VAT twice and Royal Mail's admin charge.