I have a medical billing question for the state of Nebraska.?

I am an established patient of Urgent Care of Norfolk, NE. I visited their office on 3/06, because of illness (of course). I was diagnosed with bronchitis, given two scripts, and was told if the meds didn't take affect in a few days, to return to the office. On 3/10, I returned, given stronger meds, and my illness cleared. The office, the billing agent reported to me, billed the two visits as two follow-up appts., rather than one initial, and the second one as a follow-up. The agent explained that since I was an established patient, they were able to bill me like that. That sounded fishy to me, does anyone know if what they did was legit or not? Feel free to ask related questions to further an answer. Thank you!! Rick