IRS Says No Record of My 2023 Return Filed in January - Transcript Shows N/A and Received Non-Filing Verification Letter

I'm looking at my transcript and everything shows N/A. Does this mean my return isn't processed yet? Been waiting since January and getting worried about what's taking so long. I received a letter from the IRS dated with the following information: "Information About the Request We Received On January 27, 2022, we received a request for verification of non-filing of a tax return. As of the date of this letter, we have no record of a processed tax return for the tax period listed above. If you have any questions, you can call 800-829-1040." This is concerning since I definitely filed my return back in January. I don't understand why the IRS is saying they have "no record of a processed tax return" when I submitted everything months ago. Should I be worried that my return got lost somewhere in their system? Is the N/A status on my transcript related to this letter? Has anyone else experienced this kind of delay where the IRS claims they don't have your return? I'm really stressed about this since I was expecting a refund and now I'm not sure what's happening. Should I call that 800-829-1040 number or try to resubmit my return?