They most obviously do not send it, otherwise you'd receive it & they wouldn't be refunding.

So maybe they are marking as sent or generating a label, but they then find no stock.

As casey said, probably drop shipping.

I'd be doing a few things here.

1. Strictly stick to sellers based in Australia

2. Check delievry dates- should be within a week to 10 days, no more, if Australian stock and if you are in a metro area and not in the back of woop woop.

3. Double check the seller's feedback % and comments.

If comment after comment mentions delays or cancellations, click out, move on. I'd personally be looking at a seller with an excellent % score, above 99.5% for this one if this is a category that has troubles.

Also, I'd be checking the postage details. I did see one smallish seller of this (with 100% feedback) offering free post as untracked letter. As the article is a 1kg packet of salt, that rings some alarm bells for me, despite the 100% score.

I'm not feeling that all these ads are scams, probably more like drop shipping, but just go slowly and carefully & double check who you buy from.