Hi all, sorry if this is the wrong place for this, but Im having abit on an issue on ebay and thought someone here might be able to give me some adivce.

I bought an item from a seller in Sydney about 20 days ago, paid through paypal & I went with the registered post option. The seller claims they posted the figure 19 days ago (day after I paid), I asked them for the registered number last week so I could attempt to track my parcel, but the seller is still yet to reply.

My questions are:
How long before I can lodge an item not received thingy ?

And what type of information do I need to prove my case ?
Currently all I have is my paypal invoice thats saved on ebay & the transfer info from my actual paypal account, it does say I paid for registered postage on the invoice.