Cancellation and money return is paying twice of money!

[Cherry9]

There was a traveller booked my room within 24 hours, i don't understand why it's work and without any requests, so i return him money through airbnb and i click the cancelled reservation botton as well. But now is charging me an ectra money for the money return, but there is no any cancel botton for the money return. What should i do? I dont understand why i need to pay him an extra money and i have no idea how to take them back.