Lost Item

I ordered something on Ebay three weeks ago.  It still hasn't arrived.   Seller

has provided a tracking  number.  I contacted seller, who told me she is "not having any luck with Aust Post".   Where do I go from here, please?

It depends what the latest estimated delivery date was

 

If it is no more than 30 days, open and follow through with an item not received dispute 

 

What does the tracking show?

Thank you, Sandy

.  The tracking is blank.  

You need to open the item not received dispute before it is too late to do so (no more than 30 days past the latest estimated delivery date)

 

If the seller contacts you after opening the dispute and asks you to close it and they will refund/send another. don't listen, because they won't and you will not be able to open another dispute