refund on HBO subscription

Once a subscription is initiated it will auto renew until a user cancels. If a user intends to stop using the service then they need to go into their account to do that cancellation. See or cancel your subscriptions - Apple Support

The cancellation will simply turn off auto renewal to stop future payments, it will not issue any refunds. If you want to request a refund then you can contact Apple, this is a user forum. Be aware that it is within their discretion so to whether one is granted.

This is a user helping other users with tech

questions forum, you are not addressing apple here just fellow users

try

https://www.google.com/search?q=hbo+refund&oq=hbo+refund&aqs=chrome..69i57j69i61j0l5.2317j0j7&sourceid=chrome&ie=UTF-8

and if you think apple can do it

https://support.apple.com/lv-lv/HT204084