ER co-pay not covering ER ordered services?

I have BCBSTX PPO. It’s an employer-sponsored high-deductible plan. My annual individual deductible is $5000, my annual out-of-pocket maximum is $6000, and my ER co-pay is $350.

I had a medical emergency that required me being admitted to the ER. The attending physician ordered bloodwork and a CT scan to diagnose my illness. After all was said and done, I paid my ER co-pay of $350 and went home.

A few weeks later, I received a bill from my medical provider saying that BCBSTX did not pay for my CT scan and labs. I called BCBSTX and their explanation was that I had not yet met my annual deductible, and as such, was being billed “a discounted rate” of approximately $4200 for the CT scan. (They also gave me a “discount” and labs got billed to me for $22. I explained that I was admitted into the ER for a medical emergency to which the attending physician in order to properly diagnose my illness order the tests himself and that I had paid the $350 co-pay for my visit. Response that I received from BCBSTX is that the $350 co-pay is sort of my “entrance ticket” into the emergency room and that the services rendered witness facilities are going to be billed separately.

Can I get some feedback on this? I have been to the emergency room on several occasions for various different medical emergencies (with other insurance carriers in other states) and have never paid for anything in addition to the co-pay for the services that were rendered within the emergency room or ordered by the physician attending. They did have to wheel me out to radiology for the CT scan, but that’s obvious that there would not be a CT imaging device within the emergency room.