Mainly what all the others have said.

Basically, you sent something breakable through the post, which is always risky.

Even professional companies have problems with breakages occasionally.

I had to have a refund on glasses a few years back when a couple arrived cracked and they were double boxed etc. (not through ebay)

Not a lot of point following up with Australia Post, they will just say you didn't wrap it adequately.

In future if you want to sell breakables, you could maybe go through a company with insurance (as someone here suggested) or consider marketplace or ebay with pick up only.

The buyer absolutely should have been willing to send photos. I had to with my glassware.

I get the sense you feel the buyer may be lying. This could be the case, but you have no way to know or to prove it. Neither has ebay.

So the bottom line is, if the buyer opens a claim with ebay for items not as described, damaged, faulty etc, they will win, photos or no photos.

If that happens, you will have to refund in full. I have also heard that broken glassware etc cannot be sent through the post so if you paid for return postage (which you would have to do if they opend a claim), the buyer should only send the undamaged items to you.

At this stage, you need to consider what option is going to lose you the least amount of money, because you are very likely going to lose some or all.

1. You could do nothing, claiming you packaged it correctly. The buyer may or may not know how to open an ebay claim for a refund. If they don't, then you may get neg feedback but would not lose any money. Don't count on this option though.

2. You could commiserate with the buyer, saying you are sorry this happened as you took a lot of care with packaging but you understand their disappointment and would like to offer a partial refund of X amount as compensation, if they would like to keep the rest of the set.

3. You can offer a full refund, with or without asking for the rest of the set to be returned & paying for return postage.

4. You could tell the buyer they will need to claim through ebay and you will make a full refund that way.
And if they then do open a claim,  you would need to pay it quickly. Don't let ebay step in.

What is the buyer's feedback to others like? Do they seem to be, on the whole, a happy customer?

In this situation, I personally would go with option 2. I would quickly (today) offer a partial refund and I'd offer a generous one. I know you're thinking only a tenth of the set is broken but that has effectively wrecked the point of having a set. Make the refund offer for at least a third of the price, if not half.

What you're aiming for here is to at least save some of the money and to avoid return postage costs.

Plus at the moment, you've left the buyer hanging, thrown it back on them and unelss you get back to them quickly with an offer, they are likely to open an ebay claim and you'll lose the lot.

If they won't accept a generous partial refund, I would be surprised. 

need to talk to some one from ebay about a problem

You provided broken goods,  be honourable and provide a full refund, including postage.   Simple really, not buyers issue to sort out with Australia Post or the fragile stickers, they are as protective as the paper they are written on.

Lets hope the buyer opens a not as described case and you will have no options.

The buyer does not have to  "take it up with Australia Post"

You the seller are responsible for ensuring the product is received by the buyer, as listed (undamaged).

Also, as far as I am aware, there is no obligation for the buyer to provide photos of the damage, but would be good for the buyer to comply, if able.

You will need to come to an amicable agreement with the buyer, or be prepared to pay for return with full refund.

Absolutely would have had to have been 'double boxed'

Plus things like packing peanuts or those 'air bladder' things

There have also been some suggestions that 'fragile stickers' = kick me signs

(even if not, as mentioned, Australia Post do not have a fragile service so at best they are just decorations)

How you proceed is up to you

But something like a huge set of porcelain needs far more packing than what you mention using

Was it double-boxed? You may think that you packaged it adequately but using the double-boxing method is almost certainly necessary for porcelain.

Do you think the parcel could have been dropped from shoulder height and had heavy boxes tossed on top without incurring any damage? That’s the sort of treatment one must anticipate with a courier or AP.

And… AP doesn’t offer a fragile service. The “fragile” stickers don’t offer a smidgeon more care, unfortunately.

Ask for photos, offer a generous partial refund if they’d like to keep the set, or a full refund if you want the set returned. You will need to pay for return postage.