Print the screen of it showing the provider in network. Write to the insurance company and cc to the state insurance commissioner.
Tell them that you (or the insured) called to verify and was told it was in network. Tell them you expect to have the charges covered as “in network”, in accordance with the terms of the insurance policy. Wait a few weeks....
PS Maybe send the letters by registered mail to both the insurance co and the state insurance commissioner.
Tell them in the letter that you also expect a call from a service rep of the insurer, to verify that the charges are covered in network.
Thnk you I did print the screen