Unable to receive refund server-to-server notification

we have set "URL for App Store Server Notifications"
  1. with effecting certificate

  2. support TLS 1.2

we saw refund records at https://appstoreconnect.apple.com/trends/sales
and we did not receive any refund notification from the URL we set since 2020-08-25

we have contacted Apple Developer Program Support
https://developer.apple.com/contact/#!/topic/select
with detail provided (setting URL)
(case number 101166202028)
and they suggested us to ask here

what's the problem with our setting?

Replies

09/04 we set url "A"
09/07 changed to url "B"

9/12 we started to receive S2SN on url "A"
9/17 we started to receive S2SN on url "B"

it seems there may be a delay for S2SN url to be effective
thread close.
Could you please tell me how many days did it take to get a notification after a successful refund? I got a refund of a Consumable product ( $0.99) on 2021-03-04 and Still haven't got any notification response (2021-03-05 as of today) to my serverl url configured in App Store Connect App setting page. I would appreciate for any reply.