Without all the details there's no way to respond.
You sold something.
Was this thru eBay?
Was this thru your web site or page?
Did the buyer use the Send Money feature?
Is the buyer from the same country?
Was there a currency exchange?
etc .........
As no details were shared in your post, perhaps it's best for you to contact customer support direct with your concerns as they can view your account details as no one here can do that.
