Berlindandy, nope, you can't be reimbursed the difference if you find postage didn't total exactly what you were charged. Sellers are entitled to ask more to cover postage and handling etc. Wrapping can cost more than you realise.
However, a seller is pretty silly if they allow buyers to see they have raked off too much of a profit from postage as it can be a leading cause of resentment.
I would say it is NOT normal for combined postage to be exactly the same as the total of the individual postage prices. The whole point of combined postage is to save a bit of money. It is often what tempts buyers to buy more, if they think they can get a few more items for not a lot more in postage. Of course, people realise it will be more, but they expect a total somewhere between.
Okay, you made a mistake in how you enquired, but you're not stuck with it.
You have some choices.
Firstly you could write to the seller, explaining that when you hit the tab 'request combined postage' you didn't realise it was a commitment to buy, you thought it was just a query and you could then decide to buy or not once you knew the postage. Ask if they could cancel the purchase as the combined postage is much more than you anticipated.
Your second option (if you are really desperate for these items), is to just pay.
A third option would be to... just not pay. They have not responded to your message, you could keep waiting and if it times out, it times out. This could well earn you a strike (where the seller claims non payment) but as long as you don't get another within the next 6-12 months, it does not affect you. The strike disappears after a few months anyway. No one on ebay, including sellers, can see it.
The only time it could affect you would be if you got two non payment strikes within a few months and then some sellers have their accounts set up to block buyers with 2 or more strikes from buying. But they can't block if you only have one strike.
And yes, the whole point of combined postage is usually to save a little bit on postage. Even ebay recognises this. In the link twyngwyn put up, it says.
in multiple auctions from a single seller and wants a single invoice so the seller can combine shipping.
eBay is now testing a solution that gives winning bidders up to 7 days to pay so they can make bids on additional auctions before having to pay - with the goal of saving the winning bidder shipping costs.
Personally, I'd be asking the seller if they will cancel. They don't have to and will probably ignore you if they have already ignored your other messages. But don't pay.
