Wholesale City Trading Company wholesale dress - Fasle advertisement- Not Honoring Contract- London, , Internet

I am upheld of the fact that Paypal authorizes scam artists to work with them. I have never experienced such an unpleasant experience with a paypal user.  I ordered five different items online from this online store. I only ordered the whole order for one specific item, that this store claimed that they have (false advertisement) on their site. After five days of not hearing anything from the store, I contacted them via chat, and only then they told me that they were "sold out" of one of the dress that I ordered.  So I kindly explained that I only ordered the order for this item, and if they can please refund me the money, and not send me the other items. Since they didn't have what I wanted, yet still advertised they do, I didn't want to pay for the return shipment so I begged them to cancel the order, since they said they still didn't send it. I looked on their websites and they said that they offer full refunds.  http://www.wholesale-dress.net/return-policy-a628.htmlSo , I only asked them for a refund since they didn't have what I wanted, and they didn't respect their terms and didn't agree. I pointed out everythingto the customer service representative, but they refused to cancel my order, even though they didn't have what I wanted!! and didn't send it yet!!But they offer returns don't they???
They used the fish and bait system, where they false advertise to get your money, then tell you the truth and don't allow you to cancel your order.
Then finally,after on going battles and arguments,  they returned the cost only for the item that they didn't have, but still charged a shipping cost for that Item!!I asked them, and they said that they can't refund the shipping cost for that item? What A scam!
All I wanted was the dress and after that to cancel my order...(which they didn't even send ), but they refused to do that.I am willing to return the items, but I will not pay return shipment, since they were the ones who refused to cancel.