When you say your account, do you mean your bank account?
Ebay don't pay money into your bank unless you reqest it and your money is probably on hold.
You can see what is happening with the buyer's payment by clicking Payments
You should find the sale in your 'orders' and choose 'cancel order' from the dropdown menu.
This will trigger a refund for your buyer.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)