It appears that some patients have been getting confused about the payment process for scripts/referrals, especially relating to pre-authorisation notices vs payment notices (as the patient will receive one of each = 2)
A common response to patient's who have trouble understanding this is as follows:
These pre authorisation notices and payment notices are automatically triggered from the credit card transaction process to keep you fully informed of transaction on your card.
Your original script request required a pre-authorisation of payment (similar to when you book into a hotel), the transaction is not actually processed fully at the first point it is only approved as a pre-auth and that would have been the first email notice you received on Saturday 18 Jun.
Once the doctor has received your script request and approves that they are proceeding to write the script, the automated system then process the pre-authorised payment to a full payment and that is the second email notification you received.
Once the doctor approves the script, depending how the practice has their system configured, you would probably have received an SMS to let you know the script request has been approved.
I hope this has explained the process for you.