IRS Claims No Record of My Filed Return - 570/971 Codes on Transcript and Non-Filing Letter from Memphis While Expecting $7k Refund

Just checked my transcript after waiting 3 months and I'm seeing all these codes that make no sense. There's a 570 and 971 dated for next week. My refund was supposed to be 7k but now I'm worried something is wrong. I received a letter from the Internal Revenue Service from MEMPHIS, TN 37501-1498 dated a few days ago. The letter states "On January 30, 2025, we received a request for verification of non-filing of a tax return." It also says "As of the date of this letter, we have no record of a processed tax return for the tax period listed above." This makes no sense because I definitely filed! I filed a 1040_SERIES return and was expecting around $7k back. Now I'm seeing these weird codes on my transcript and getting this letter saying they have no record of my return being processed? The letter says if I have questions to call 800-829-1040, but I've been trying that number for days with no luck getting through to a real person. Anyone know what these codes actually mean? Does the 570 mean they've put a hold on my account? And is the 971 code related to this letter I got? Getting stressed cause I really need this money.