I updated it to two stars only because my issue was finally resolved by calling the Patient Advocate for Core Institute. Jason was very helpful and understanding and within 2 weeks he got them to relent and give up on billing me where a billing was not warranted. It is unfortunate that the Central Billing Department NEVER ONCE directed me there out of all the people I talked to they just kept insisting that it was a "valid billing". Thank heavens for Yelp or I would still be fighting this and they would have put it against my credit.