Last August, my wife was getting a treatment and a provider sent a bill. At that time, she had two insurance - individual and from work. I called to the provider and specified both insurances and was told everything is OK, put the bill aside. I do not know what they were doing for six months, but only in February we received an EOB from the individual insurance with a waiver due to pre-existing conditions and, immediately, another bill from the provider. Called them again and asked if they claimed to the second insurance? Got an answer: Oh, everything is OK, throw out the Bill, right now we going to clime the second one. Yesterday I received an EOB from the second insurance with refusal by reason: the time frame for claim submission has expired.
Obviously, this is a provider's fault. But it looks now, like I'm responsible for this debt. Is there any way to resolve this situation?

