“Purchased item online, merchant called and told me...”

Purchased item online, merchant called and told me he refunded money and that I had to purchase agin for order to go through. Waited till money was refunded and purchased item agin. Second attempt to order item was told money refunded agin and merchant informed me his card company made a mistake and that I would have to purchase item a third time. I have waited two weeks and still money not refunded. Merchant claims he has not received payment although I have proof of payment. Scam alert.