Weemss is designed to make accepting payments easier for you. The platform isn’t a middleman in the transactions, you receive the money from every sale directly in your merchant account with the payment processor that processed the payment. To refund a customer you need to go to that merchant account and find the refund option there.
Here are some links to help articles about refunding payments with the payment processors in Weemss:
Important: You have to remove the refunded payment in Weemss as well, to make sure the data you have in the system is correct. You need to go to Registrations, open the order that was fully or partially refunded, and make the necessary corrections from Actions > Payments.