We sent 5 years of amended returns (all separate envelopes) as part of a voluntary disclosure program, mailed in March 2020. They cashed the checks soon after, but then in December 2020 I got a letter saying they lost the 2018 return and could I mail it again please. Then in Jan they asked for 2015, and soon after yet another request to resubmit 2016 because they lost the return. So then we pre-emptively resent the years they had not yet told us they lost. Grrr. None of the amended returns, re-sent or otherwise, have been processed.