have you checked to see if the IRS has a transcript of your return?
you say "record of your account" the IRS has several different transcript types
Tax Return Transcript - shows most line items from your original Form 1040-series tax return as filed, along with any forms and schedules. It doesn't show changes made after you filed your original return.
Tax Account Transcript - shows basic data such as filing status, taxable income, and payment types. It also shows changes made after you filed your original return.
Record of Account Transcript - combines the tax return and tax account transcripts above into one complete transcript.
note that none of these specifies it contains all the data contained in your tax return.
obviously, the IRS had to have received your return but evidently something happened to your original filing.
no sense mailing a record of your a/c because the IRS has it.
you either mail a complete copy of your return, I worry about late filing penalties because the letter says they did not receive your return which is ......
or write back, include the letter, that I have reviewed the record of my account, and based on what it contains your contention that you never received my return is bogus. (or use your own wording). let me know on how you want to proceed in this matter.
another option would be to contact the Taxpayers Advocate Service office in your state before doing anything. They may not be willing to help in this matter but it doesn't hurt to call.
https://www.taxpayeradvocate.irs.gov/contact-us/#FindlocalTAS
