put https://api.paysimple.com/v4/payment//reverse
Refunds a settled payment of the specified Id.
- Any payment with status Settledcan be refunded via this endpoint.
- To cancel a payment within the void window (prior to the CanVoidUntil), call the Void Payment endpoint.
- If the payment is past the void window, you must wait until payment is in status Settledto refund the payment
The refund call results in the following actions:
- The Statusof the original transaction is changed toReversed(shown as "Refunded" in the UI).
- A new credit (negative) transaction is created with a Statusof:
 Authorizedfor Credit Card refunds
 ReversePostedfor ACH refunds (shown as "Refund (Posted)" in the UI)
- The ReferenceIdfield for the original transaction is set to the Payment Id of the credit transaction.
- The ReferenceIdfield for the credit transaction is set to the Payment Id of the original transaction.
Testing Refunds in Sandbox
To test a refund works in Sandbox, you must have a payment in status Settled.  You may either wait 3 business days for the system to mark it as settled, or call the following endpoint to mark the payment as Settled manually. This endpoint works only in theSandbox Environment.
PUT v4/MarkPaymentStatus
{
	"PaymentId" : 123545 // The PaymentId of the payment to mark as Settled
}