Actually all photographers here on Fiverr ask buyers not to purchase their gig untill they actually got the product.
Shipping can take months or not go through at all, then there’s customs and all that. That is a reasonable demand, there is simply no other way to operate sadly.
Of course that’s far from ideal (and one of the main reasons why I decided against creating a photography gig for myself, although I really want to) and it would be great if Fiverr could look into a different format for photography category to make it possible to make it official from the start (perhaps milestone-like system that wouldn’t start the timer untill shipping is successfully done?).
If the seller confirmed he got the products, it is unlikely his intention was to scam you.
Does he have any reviews? Have you made your intention on placing an order asap clear? (I ask because maybe something went wrong in communication and the seller thinks you expect him to start working without upfront payment, but he doesn’t want to confront you). How long has he been ignoring you? If it’s just a couple of days, I would give it more time. Perhaps he’s busy with something else or something happened. Ignoring your buyers for too long is unprofessional of course, but there is still chance he would deliver a good result eventually, within a reasonable time frame, even if communication is lacking.
Unfortunately there’s not much you can do anyways, as Fiverr can’t protect you if you haven’t made a purchase. If the seller doesn’t get back to you for way too long or you don’t recieve your products back, you could try contacting customer support about getting this seller’s account suspended for fraud.