V rare for such a thing to happen. a seller with 99.3% feedback and a huge number at that means he is pretty genuine. also check out the negatives and see for what all reasons they have come. that will give some assurance.
i think i m the only one selling S300 at 18999. my previous listing which was 10 months old and had more than 25000 visits got ended abruptly when last two pcs got sold suddenly. normally when qty left is one, i get a little more stock and amend the listing, this being exp item.
if its from me that you have bought the item, i m sure you would be receiving the item shortly. do leave a follow up comment on this forum as well about your experience which we are sure would be pleasant.
regds