Why am I getting charged 65$ for a new card without an active subscription from Apple?

Check your Purchase History here. It sounds like you had a previous purchase that was unable to be processed due to the expired card, so when you add the new card, that charge will then be processed. The purchases history will show what the charges are for and amounts in red or labeled as Pending mean they still have not been able to be processed yet.

View your purchase history for the App Store and other Apple media services - Apple Support

You cannot cancel a pending payment. This would have already been authorized by you with the amount showing on the screen before you double clicked the side button, followed by verification with FaceID or Passcode. It makes no difference if you use the service as Apple is not tracking your app usage and is the same as having a Netflix subscription and not watching any of the shows, you will still be charged for it.

To cancel any current subscription, that is done here:

View or cancel app subscriptions on iPhone - Apple Support

After the pending charge is able to be processed, you can request a refund here, but note that in most cases all transactions in the App Store are final. On occasion Apple may provide a compassionate refund, but it should never be expected. It is not possible to request a refund on a pending charge.

Request a refund for apps or content that you bought from Apple - Apple Support

Jumialurd wrote:

So that means that I must pay the amount being charged before I can fully use my account ?

Not sure what you mean by fully use your account. If you mean to use the App Store to download/update apps, then yes. Other than that you can continue to use your device with the apps that are currently on it.