After you file

I submitted my federal and state return 03/13/21 and they were accepted the same day. I received my state return 2 weeks later but still have heard nothing in terms of federal return. I tracked my federal return online with the where's my refund tool and it was saying processing for the past 2 months. I logged on today and they now say that they have no record of my return and I am past the due date to file. I have tried to call a dozen times and cannot reach anyone at the IRS, all automated messages or they hang up because call volume is too high..... What do I do???