Couchsurfing Charged Me Without Permission — How to Get a Refund Fast

The Couchsurfing app charged $9 from my account. I want a full refund of my money. I don’t know where to apply or how to reach anyone about this issue. I can’t call the website or find a support number. I’ve been left in a difficult situation — please help me. I want my money refunded as soon as possible. Because of this, I may even have to cancel my credit card.