After you file

I filed Jan 2019...I have yet to get my return.  I submitted the last of the final documents they needed October 21,2019...got a letter they would respond by February 8,2020...nothing...got a letter last week that they have had a large volume of inquiries and they would complete my review by March 19,2020.  This was proving my EIC was legit..i had to prove my kids were my kids... MEANWHILE..my 2019 return has been fully processed and refund deposited in February.  WITH THE SAME KIDS!!!!  like wtf....how does this happen.  You approve them on my 2019 return but can't hit a button approving them for my 2018 return which is now MORE than a year old!!  SMH