How can I dispute unknown charges on Apple Account?

See the following support document to find and identify the charges.

click here ➜ If you see 'apple.com/bill' on your billing statement - Apple Support

If you are the Family Organizer in a Family Sharing group see the following support document to find other family member's purchases that are charged to your payment method.

click here ➜ Get help with charges from apple.com/bill - Apple Support

If you share your payment method with anyone, check their accounts.

Use this link to check on Billing questions. Subscriptions and Billing - Official Apple Support

You can also take a look at this support link about charges on your Apple Account. If you see 'apple.com/bill' on your billing statement - Apple Support

If you don't see the charges in your Purchase History, then that means the charges are not managed by Apple. What is the exact description of the charges you see on your billing statement?

Note that this has to be your billing statement, not an email/message claiming you were billed for a charge.