If the subscriptions are tied to the account you don't remember, you will need to remember it to cancel them. There is no way to cancel a subscription if you cannot log into the account it is tied to.
For any successful charger apple would send an email receipt to the attached email address. Are you not seeing these receipts?
Start here: link-> If you forgot your Apple ID - Apple Support
Then here: link-> If you forgot your Apple ID password - Apple Support
Once you regain access to your account, then you can log in to it and cancel the related subscription.
Some subscriptions can be cancelled on an Android device, like Apple Music.
For others you will need a computer (PC or Mac) to cancel them.
From the support document you came from:
If you don't have an Apple device