I am a ebay.in seller and I usually list a single piece product. When a buyer buys it, instantaneously it is taken off the listing because the quantity then goes to zero.
Not getting a tracking code or the item, that too in weeks after you buy it is another matter and you should raise a complaint about it.
If you got refunded without asking ebay to, then the seller didn't dispatch your item (may be it was later sold to other buyer, or that item was taken down by the seller -- may be he couldn't get it from his supplier in time to send it over to you) and ebay automatically refunded your payment, which was held by ebay and not given to the seller by it, after the seller's time limit to dispatch it AND upload its tracking ID on ebay was over.
Has the transaction completed? If yes, request a refund from your credit card service. (Charge back)