While the seller may seem suspicious, it is all speculation whether or not it is intentional. Things happen life and it may have been a very busy seller who got confused or not computer savy. You really don't have any proof either way and speculation is simply just that, and that means you are as right as you are wrong. What you can do going forward is to be more careful with your next purchase; not buy from this guy again; and/or buy your future animals in person.
On a side note, I can confirm that this type of shady practice does happen on the dog/cat rescue business. While many are legit, some are not, they intentionally post pics of cute puppies and kittens or a particular rare breed or high demand breed that was, at one point, up for adoption. The animal is usually already long gone and adopted but they would leave it as available on the petfinder site and their website to lure in potential adopters. Or, they still have the animal but plans to keep it until they had collected enough donations for the animal's tragic story.