Yes, you can easily issue a refund.
Payments collected via the system are immediately transferred to your PayPal account.
If you wish to fully or partially refund the payment – you can do so by visiting your PayPal dashboard, login with your email and password, and you can see all the payments from your clients. Click details next to any payment and you’ll be able to refund the payment.
If you are using Stripe you can easily issue refund from your account dashboard. Click here to learn more.