Refunding of the money for the ticket could be performed if the payment has been made. Enter a closed ticket, press the "Return" icon in the upper panel, choose the service or the goods to be refunded. The cash register would perform an expenditure.

Refunds report
Refunds report is available in Analytics → Finances section. This report would show all the data on refunds on goods and services. Later an option of a "one-click-fine" to an employee will be added, if the refund was made due to his fault.