refund not received

You may have slowed down processing of your return by both efiling it and then mailing a copy. You should have been able to track your efiled return soon after it was submitted and accepted using the IRS tracking web site. First confirm that your efiled return was submitted and accepted by the IRS:

https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp

If it was accepted, what does the IRS tracking web site say about the status of your return:

https://www.irs.gov/refunds  Make sure you use the federal refund only when logging in to the site and not your combined federal and state refund.

The IRS has been very slow to process returns this spring and summer due to the pandemic. Refunds are taking much longer than usual. 

Here is an IRS Q&A with information about refunds:
https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions

See this info about the current status of IRS operations:
https://www.irs.gov/newsroom/irs-operations-during-covid-19-mission-critical-functions-continue

You can try contacting the IRS by phone using this procedure:

Call the IRS: 1-800-829-1040 hours 7 AM - 7 PM local time Monday-Friday
When calling the IRS do NOT choose the first option re: "Refund", or it will send you to an automated phone line.
So after first choosing your language, then do NOT choose Option 1 (refund info). Choose option 2 for "personal income tax" instead.
Then press 1 for "form, tax history, or payment".
Then press 3 "for all other questions."
Then press 2 "for all other questions."
- When it asks you to enter your SSN or EIN to access your account information, don't enter anything.
- After it asks twice, you will get another menu.
Press 2 for personal or individual tax questions.
Then press 4 for all other inquiries
It should then transfer you to an agent.

You e-filed and mailed the same tax return?  Was your e-file accepted?  What do you see when you check the status of the e-file?

https://turbotax.intuit.com/tax-tools/efile-status-lookup/

If the e-file was not accepted, then you are waiting for the IRS to dig through the pile of unopened mail that has been stacking up in trailers for months during the pandemic.

Per the IRS website IRS Operations During COVID-19: Mission-critical functions continue: The IRS is not currently able to process individual paper tax returns. If you already have filed via paper but it has not yet been processed, do not file a second tax return or write to the IRS to inquire about the status of your return or your economic impact payment. Paper returns will be processed  once processing centers are able to reopen.