Advice needed - Filed multiple 1040NR - No reply from IRS after many letters/calls for >2 years.

I have a question I am seeking to get help with.  

I am a non-resident filer (living in Australia) so I am filing a 1040NR manually each year (as you cannot efile these).  These are refund returns.  

Since COVID I have not been getting any reply from the IRS to any of the returns I have filed.   It is now over 2 years since I submitted/filed my last return that they have not processed.  Since then I have send more returns, duplicate copies  (as I was worried it got lost in International mail) AND a letter I sent asking for information on what the status of my last few returns.  Still no answer from the IRS. 

I have tried calling the IRS but keep hitting a dead end of trying to find someone who can answer any questions.  

I am very concerned as the returns I submitted in 2020 is now approaching the deadline for refunds and I have no idea what the status is or where to get help.   At least in Australia I can speak to a human in the ATO but the IRS is a big black hole. 

I do not know what I can do it find anything out.  Looking for advice.

Thanks