No 1310 attached,  but a copy of the Letters of PR and the death certificate.  

Went to the IRS website for this.  They require a credit card and phone number for the decedent.  I think I have read somewhere that if you try that and it fails, you are locked out forever.  So this morning I tried calling the IRS number on the notice.  After listening to the recorded spiel about using the website, the message says that they are too busy right now so call back later, or another day. 

My clients aren't in urgent need of the $1,700 refund and I have told them the best way to get IRS attention is with a Congressional.  Might try a Form 911 first, to see if Taxpayer Advocate ignores it like the last one I filed.  (IRS ignored Tax Court judgment and assessed a higher amount of tax.)