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

Okay, therefore, I need to pay my doctor's invoice. I visited the website and it says I need a account number. But, I am missing that! What am I supposed to do? Is there a way to retrieve my client ID? Can someone figure this out. It's really bothering having to stop payment because of this. Veradigm and Pay My Doctor: How to Use It Navigating h