IRS wants to know why Turbo Tax has taken my $1646.00 refund, saying that I owe when I di not actually owe anything!!

Neither  Intuit nor the TurboTax program never handle any fed/state refunds of any kind ... it is against the law because they are not a bank.

If you requested to have the TurboTax account fees deducted from your federal tax refund, the IRS will send the refund to a third party processor to have the fees and the service charge deducted. The third party processor will deduct the TurboTax fees plus the service charge and then attempt to direct deposit the remaining refund balance into the account that you entered on your tax return.

For the status of your tax refund you will need to contact the third party processor, Santa Barbara Tax Product Group, using their website - https://www.sbtpg.com/

Tax Products Group Contact Information - https://help.sbtpg.com/hc/en-us/articles/230084587-Contact-Information
On this page you can also scroll down and click on Submit a request

Or https://taxpayer.sbtpg.com/

Call 1-877-908-7228