I filed my return by mail and am due a sizable refund. It has been seven weeks since I mailed the return. I checked the IRS website and they have no record of my return. The IRS phone numbers that I have called have not allowed me to connect with a person to ask what I should do. What is your recommendation? File another copy "return receipt requested?"
The IRS has not been processing mailed returns for some time. Returns are sitting in trailers near processing centers unopened. It would not do any good to mail another return that gets added to the stack. You will not be able to track the status until the IRS opens your return and begins processing it. They have not said how long it will take them to catch up with the stacks of unprocessed returns.
Once the start processing your return, you can track the status using the IRS tracking web site: https://www.irs.gov/refunds
No one at the IRS would be able to answer any questions about it until they start processing it.
See these Q&As about the process: https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions