-$1200 Scammed, Help me Please!

Hi,
Few days before a guy paid me $1200 money from my website PayPal merchant button. [June 27, 2014] [Buyer use Credit Card for payment.]
But due to some reasons he want to cancel this Order and we both party settlement on $945 payment.
I (Seller) return $945 payment to Buyer thru Bank Account [July 09, 2014]. I have bank receipt of payment made and mobile SMS alert for debited $945 money with me.
NOW, after few days Buyer made full $1200 payment dispute on [July 12, 2014]. I am so…
-$1200 Scammed, Help me Please!

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