Not receiving "REFUND" notification from Sandbox

We have auto-renewal subscriptions and we implemented beginRefundRequest, but we are not receiving "REFUND" notification from the Sandbox. We are using server to server V2 notifications. When we submit a refund request, we are getting "DID_CHANGE_RENEWAL_STATUS" notifications, but not "REFUND" notification. We are using storekit1 for subscription process. Thanks in advance.

Not receiving "REFUND" notification from Sandbox
 
 
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