Does refund cost money?

Good day, I have a question regarding refunds. Specifically, I'm wondering if there's a cost associated with requesting a refund for a transaction made in cryptocurrency. As an investor and frequent user of digital currencies, I understand that the market can be quite volatile, and sometimes unexpected events can occur that lead to the need for a refund. I'm curious if this process, particularly in the world of cryptocurrency, incurs any additional fees or charges. Thank you for your time and attention to this matter.