Labcorp

So I've received a letter in the mail 4 months later for NIPT which my insurance had covered.

I received a letter from my insurance company notifying me I owed nothing. I was so happy!

But now LabCorp wants close to 4k!! And is saying my insurance paid nothing.....

I'm just confused on what to do really.

I'm going to call LabCorp up in the morning and ask wtf is going on because it's ridiculous.... I'd not have gotten the nipt if I knew for sure my insurance wasn't going to cover it fully.