Help please for Labcorp billing question, my TB skin test

is positive, I know that can be a false positive, so I ask the doctor to do the TB blood test. I search online to see which lab to go, at that time it shows in labcorp website, they charge $120 for that test, I tried to call the local labcorp office to confirm the price twice, but for some reason the people who answer my phone hang up on me, I also notice in their local lab\'s website it showed no appointment needed just walk in. So at last I just decide to go there directly and did the test. But days later my insurance company send me the paper showed that they charge $248 instead of what it shows in their website $120. I call their national billing office 2 times, they told me that\'s how much they charge for this test, deny their promotion on website. I call their local customer service again, a supervisor told me because the promotion is only for the patients who doesn\'t have any insurance who pay cash directly, because i show my insurance card to them so they went through the insurance so they can\'t get that price for me. The fact is that in their promotion it doesn\'t mention anything about the limits for how to get that price.....