If it comes thru again wanting you to pay that charge, demand that they provide you with an itemized bill. It SHOULD provide ICD9 codes for each item which you can then google to see what they are. If not, insist that they go over it, line by line, and explain each charge.

As for whether they're part of your network, maybe try call the insurance side & see what they show. I had to have Anthem make sure MD Anderson was still on ours before our last trip. (It's still on our OUR Anthem plan but was dropped from a lot of others. Too many people were travelling there for treatment & its cheaper for insurance to have patients treated closer to home..)

p.s. "OFFICE O/P EST MOD 30 MIN" means that the provided an approx 30 MINute OFFICE Out/Patient appointment of MODerate complexity to an ESTablished patient." Fun, huh? (A little leftover from my days working for a software pharmaceutical company.)