SETTLE|MY|YOUR DOCTOR CLIENT ID: WHERE'S MINE?

So, you just want to pay our doctor's bill. Easy, right? Not so fast! The website says I must enter my Client ID, but where is mine? This whole thing is driving me crazy! I've checked everywhere, but this darn Client ID looks to be gone. Perhaps I just missed something? Should you call customer support?? Help! This is truly a headache. Un