My 2020 Federal Taxes, were amended and accepted on 4/28/2021. I am due a refund. IRS.gov site says there is no record of return. TurboTax says they can't help. Now what?

Even during “normal” times it takes about four months for the IRS to process an amended return.  During the pandemic and due to the severe backlog at the IRS it is taking much longer—six months or more for many amended returns.  Do not expect quick results from amending.  When the IRS issues a refund for an amended return it will be by check.  They do not make direct deposits for refunds for amended returns.  You can watch for information here:

https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1

Thank you. It concerned me that IRS.gov said there was no record of the return. Do you know if they only show a record when the refund is processed?

Nothing will show up until they start working on it and key it into the system.   All you can do is wait--there is not a way to speed it up.   If you amended in late April, be pleasantly surprised if they process it before the holiday season.