Mistakenly subscribed with wrong Apple ID

While you are welcome to contact Apple, why don't you just cancel the subscription and subscribe again with the correct account?

Refer to this page for Apple Support features ➔ https://support.apple.com/contact

Select from the presented options until you find a solution for your issue, or see if there is a chat or phone call contact method offered lower on the page under “Get more help” (you sometimes have to narrow down the options multiple times before this is shown). If you do not see your issue, keep experimenting with any series of selections until you reach one that offers a chat session or a telephone call and get the representative to redirect you.

This support article has various country telephone numbers for contacting Apple for support and service ➔ https://support.apple.com/106932 Scroll down to “Connect with live support”. If your country is not in the list, go to the “Other countries” entry at the end of the list and click on the “options” link. Not every country has telephone support, and phone numbers may only work when calling from the same country.