FRUSTRATED PAY MY DOCTOR: WHERE'S MY CLIENT ID?

Okay, right, I need to settle my doctor's invoice. I went the system and it says I need a account number. Unfortunately, I don't have that! What am I supposed to do? Is there a way to retrieve my client ID? Please figure this out. It's really frustrating having to stop payment because of this. Veradigm & Pay My Doctor: A Guide Navigating your me