The IRS just mailed my mom a form 12c asking her for two forms on her Marketplace (Obamacare) health plan - a form 8962 , and form 1095-A before they will mail her her tax refund. The problem is that this is a mistake. My mom is 90 years old and has been on Medicare for many years, she does not have a Marketplace (Obamacare) health care plan, never applied for one, and was never mailed the forms the IRS is asking about. They mailed us a letter asking for the forms to be returned within the next 20 days, or gave us a fax number to send this information which we do not have. Here is my question --- Would it be best to call the IRS to tell them this is a mistake -- which could result in very long telephone hold times, which is hard for my Mom since she is too unwell to sit up on the phone for hours on hold, fax a reply to this effect to the fax number that was given, or send a certified letter which I have already written that I will have my mother sign to the address given on the first letter with all supporting information that my Mom is on Medicare and never has a Marketplace health care plan, and that this information request was made to us in mistake? Thanks for your advice in advance.