That'll be the new ebay scam, otherwise known as 'global shipping'. Someone needs to look into this, as I suspect it's illegal.
Take today - I looked at an ebay item. Postage to me, £3.34 by RM signed for. Put it in to buy, then noticed postage was now 'international' at over £10. So they offer one price but charge another. I call that fraud.
I've had other instances where postage (to me) has jumped by £30. Yup, ebay's 'global shipping'. I keep telling sellers they will lose business by using gs. I'm led to believe also that if a seller chooses to use gs, he / she cannot unsubscribe from it. The whole thing stinks.