eBay Buyer Won't Pay for Item - Scammer?

I had sold an item recently and the item had a bidding option and a buy it now option. With a day and a half left on the auction a lady had used the buy it now option for $150. I then sent an invoice and e-mails waiting for a response and three days went by with no reponse or payment. So through ebay I was able to get information on the buyer and the phone number. (This buyer by the way has 0 Feedback and just signed up for the account) I called the buyer, which when she answered was surprised when I told her who I was. I asked her why she hadnt paid for the auction. She was very nervous and said that her sister was the one that bought it with her ebay account and decided to buy something locally instead and now does not want the item. Is this considered a scammer and what can be done about this other than the UPI which only gets back final value fee after having to wait a month for finalization.

eBay really needs to change their rules as I cannot see how eBay is legally still running,