IRS Notice and Transcript code 570/971 for prior year return and holding Refund

[DAH94]

I e-filed on 03/26/20 due to my job sending out W-2s late, my return was accepted on 03/27/20, and a few days after that I'd been checking WMR. Today the progress bar disappeared, and all I could see was text showing "Your return is still being processed, we will update when a refund date is available." Never saw this before, so I logged on to my IRS account and saw my due taxes from last year were cleared with a balance of 0.00, but 2019-2020 show N/A. When checking my account transcript it shows codes 570 and 971 Notice Issued. I did have to file an amended return for 2016 which I sent certified and was signed for by them on 02/14/20. The line 570 shows account under review and references my 2016 return showing a notice to verify non-filing dated today 04/14/20. It looks like they're holding my refund of $1342 saying I didn't send them my 2016 1040X after 4 years, but I still have the certified letter receipt with a signature. What can I do since I can prove I did my part, and needlessly held my refund?

[DaveF1006]

Do you have a copy of your 2016 return? if so, send them a copy of the return, the certified mail receipt showing that you submitted, and a detailed letter stating that you did submit. it wouldn't surprise me to know that it is probably warehoused somewhere but never got processed.  Since it was mailed in, human error is probably the culprit.  

Three weeks after you mail your amendment, you can start tracking its status at the IRS Where's My Amended Return? site or by calling their automated number 1-866-464-2050. Please note that it can take 12-16 weeks to process your amendment. Follow up with them constantly to make sure they receive the return.