Order cancellation overdue

[huweis0]

I tried to sell an item with a buyer living in another country, too distant for delivery. We both agreed to not sell/buy the item. Due to him having already paid the item for the listing's price, he had to fill an order cancellation. Since I was unaware that I needed to confirm the cancellation, the cancellation became outdated. When I realized this, I tried to make another order cancellation but couldn't due to the existence of the cancellation I failed to accept. Now I cannot cancel the order and would really appreciate if someone could tell me how I should proceed to cancel the order and for my balance to automatically refund 100% of the buyer's money, if possible, without me having to pay extra fees for the order cancellation. 

Thank you for your time.