This story seams par for the course when dealing with insurance companies regardless of if it's startup or not. I've had the same exact issue with everyone from "United" to "Humana" and more recently "HealthNet" You will be told something is in network and it's not, a lab location is listed on their website as in network and then they claim it's not covered later. Sadly, this seems to be an area where legislation needs to bring out the big stick and force them to cover services that they had listed as "in-network" bad data is no excuse.
Wish more people knew this. A lot of professionals on here might personally have a stellar health insurance plan through their employer that covers almost anything no questions asked, but those same big insurers will administer cut-rate plans to the majority of plan-holders and deny payment at the drop of a hat, or pick and choose what necessary care / medications they will / won't pay, often after the fact, seemingly arbitrarily or if submitted paperwork isn't flawless.
It's a pretty good racket really; provide quality, hassle-free coverage to the high income, professional class, or anyone else that might have any say or sway or influence in government, and then for the working class majority refuse to ever pay out more per person than you are payed. That way you can cost-save like crazy and make obscene profits, but no one that matters cares and based on their experience it just looks like belly-aching and blowing things out of proportion.
