Why didn’t I receive my advance once my return was accepted?

See this resource for more information: 

Offer details and disclosures for the Refund Advance program

The IRS is not officially accepting returns until January 29. 

Okay. So why is TurboTax saying I was accepted?

The IRS does a test period before opening. You could have been in a test group, but still the IRS does not officially open until January 29.