How to figure out these charges

I just received a bill from a recent endocrinologist appointment in March. I have Florida BCBS and my specialist copay is $50. I paid the $50 at the appointment and went back the next week to get routine lab work done.

Now I received this bill with charges: https://imgur.com/gallery/uYeZ1Yn

How can I figure out what these extra charges are for and whether or not I should have to pay them?

For example, in my EOB, it states HbA1C lab tests are covered 100% – no deductible, but I am charged for it, and looking at that claim only $16.99 of the $34.00 was a covered expense.

My EOB also states that preventative care lab services are covered 100% – no deductible, so why the lab charges in the first place? Unless these lab test for T1D don’t qualify under preventative care, but I would assume they do because every endo I have had for the past 20 years has requested them annually to make sure no other health issues come up.

Why a $70 charge for glucose monitor up for the claim for the office visit. Idk what that is but maybe it is also an HbA1C test.

Who do I contact, the doctors office billing, my insurance, and what do I ask them to make sure things are getting covered/billed correctly?