For $214 there is no rational upside in sending a lawyer.

You seem to be doing a lot of phone calls. You should stop speaking on the phone about this. Send a letter, on dead tree, "return receipt requested" to Accounts Receivable at the clinic. Say that you talked to A, B, and C on X, Y, and Z dates, that their staff has accepted that this is a data problem on their end, and that they should promptly re-code this and re-submit to insurance. Tell them that, if they fail to do this and instead send this to collections in error, you will explore your remedies under the Fair Credit Reporting Act and other avenues which are available in your state.