Midi/ insurance communication nightmare

I booked an appointment with Midi. I used their calculator and it said that I wasn’t gonna have to pay for the visit based on my insurance. A full year later I get a notification from them that I owe $185 for my visit. I’ve called them multiple times and left messages because you can’t get through to a live person. Nobody calls back. I’ve emailed them multiple times and they say they’re looking into it. I can just tell you I would never go and pay $185 and why did it take you a year to send me a bill that’s right it’s been a full year since I actually had the visit and now they want $185