I changed accounts on an app, but Apple ID still puts subscription on the old account. How do I associate my new account on this app to Apple ID?

2 years ago, I bought a subscription on the Apple Store for the app Discord.

A few months ago, I deleted that account and made a new account for Discord. However, whenever I try to buy the subscription from the Apple Store, it keeps giving the subscription to my old, deleted account. It’s showing errors when I try to put it on the new account.

I contacted Discord, and they said the reason why is because when you first download an app and make an account for it, it will automatically become associated with your Apple ID. They cannot help, and told me to ask Apple how can I make Apple ID know I changed account info on the app and start giving the subscription to my new account.

Any help would be appreciated, thank you.