as it is..as long as the item has not changed hands..
it still belongs to the owner on how he wants to disposed of it..
an offer to sell with a firm offer to buy still need a confirmation to sell (consideration stage)
so if seller doesn't reply and choose not to deal with this particular buyer..it is his choice and decision. Doesn't means 1st sms or email gets the item unless specified so.
and there will be other similar items on sale too..so there is no need to kpkb..
there are really weird pple out there these days..