I know people are not going to like my response to your matter, but if it states in the listing " will not take responsibility for items damaged in post without insurance" even if the insurance from AP doesn't cover it then sorry your out of luck (maybe they mean self insurance). I do feel for you though, no one wants to receive something smashed up.   Maybe the seller should have packaged it better, that is what feedback is for. You are esentially holding the seller responsible for something out of their control.   I also wouldn;t put a fragile sticker on anything.   You agreed to the terms of sale when the purchase was made.

Whether AP have a fragile service or not is irrelevant. Registered post only covers for loss, not damage. A seller can put anything they like in their TOS, but in the end they are responsible for getting the item to the buyer in the advertised condition. I can't see how the OP could have paid for insurance, as that only kicks in for $100 and over. In fact, they did pay for non-delivery insurance (the only sort available from AP) by paying for registered post.

Sprinkles, the seller is AP's customer, not you, so there is no point you trying to claim anything with AP, except to get them to confirm whether the packaging was acceptable or not.