I never received a 1095-C. My refund was delayed. I just received a notice from the IRS asking for copy of 1095-A. I get my insurance through my job not the Marketplace.

Who is supposed to send out the 1095-C? My employer or my health insurance company? I asked my HR department who informed me they do not mail out 1095-Cs. And why is the IRS asking for a 1095-A when they should already have a 1095-C on file. I was scheduled to receive my refund weeks ago and don't know how to resolve this.