Insurance notified me a week after a CT scan that I needed to go to an outpatient center for pre-authorization – did I screw up here?

I have been having some long standing abdominal pain. My primary care doc initially assumed it was related to another muscular issue, but since the original issue resolved and the abdominal pain was still present months later, he wanted me to get a CT scan to see if something serious was going on.

My doctor (part of XY medical group) put in a referral on DAY 1 for a CT scan at XY medical center, a larger hospital. On DAY 3, I got digitally notified via my doctors office that the referral was approved and to call the radiology number to schedule the scan.

I called and the scheduler wanted me to come in the same day for the scan. I thought that was rather sudden, but I had time that day so I went and got it done on DAY 3.

DAY 4, my doctors office called and told me not to get the scan done at XY Medical Center because it was out of network. I told them I had already completed it and the scheduler didn’t mention that at all, they were equally confused, but it was left at that.

DAY 10, I receive a letter from my insurance company that they want me to go to AB Outpatient Radiology to determine if the scan was necessary and to get it done there. They don’t list an address or a phone number for AB Outpatient Radiology, and googling AB Outpatient Radiology leads me to a site called CD Outpatient Radiology, but the two seem to be the same.

I haven’t received a bill yet, and I knew from the beginning that I would have to pay a bit since I’m on a HDHP, but now I’m worried that it’s going to be an insanely large bill since I got it done I guess without authorization.

Before I had the scan done at XY Medical Center, I verified on my insurance website that it was an in network center, but I guess the radiology aspect isn’t in network? I now know I should have called my insurance prior to having the scan done, but this is my first time dealing with this sort of thing and I assumed if XY Med was scheduling me, then they had gotten approval from insurance.

Does anyone have any insight onto how screwed I am, or what I did wrong here?