Upon your confirmation, the coins might be refunded only under one of these circumstances:
If any price change above 5% during this process
If the sell request passed the overdue time
if the amount you sent is below the requested amount (underpayment)
Before any refund transaction, you will be asked for your confirmation on the refund and on the deposit address
Cases where you overpaid for the sell coin are not considered as a refund case, and sell coin transactions will be proceeded with the sent amount.
Please also be aware that fees will be applied on refund transactions by the network