Setting subscription to inactive in google playstore

Do not waste your time trying method using google play developer api mentioned by rkunboxed, it doesn't work.

You will get the following response:

{
  "error": {
    "code": 403,
    "message": "Deleting a published subscription is not allowed.",
    "status": "PERMISSION_DENIED"
  }
}

For more details, see:

https://developers.google.com/android-publisher/api-ref/rest/v3/inappproducts?authuser=2

After contacting google support I got the following response:

Thanks for contacting Google Play Developer Support.

As you've noticed, no subscription can be deactivated once created. You can hide your current subscriptions by removing reference to them in the code, but the Play Store Listing for your app will always include the prices of such subscriptions because they exist in the Play Console. This is working as intended. It is recommended that you never use 'fictional' (as you put it) prices when testing your app's functionality.

The only way around this would be to start over with a new app and package name, taking care not to create any fictional subscription items.

Not the answer I was hoping for.