i got sent to collections over a medical bill i never received. my insurance was valid and on file, not only that the hospital was able to bill my insurance successfully. i didn't know about it but apparently there was a third party that also billed for pathology services. i figured because the hospital billed me everything was kosher.  the way it looked was as if they never even sent the bill to my insurance either. i can see all my medical bills in an app and everything looked good. its as if some brown skinned diversity hire in a billing department wasn't able to operate a computer to get my information. i disputed it with the credit bureau and they eventually removed it after denying first.
United States