Why haven't I got my second stimulus yet it sent it was deposit into a banking account that I've never seen

That bank account was a temporary account that was used to withhold your TurboTax preparation fees from your 2019 refund.  The IRS made a processing error that has since been resolved.

Please note the following update: 

We are happy to share that stimulus payments will begin to be deposited on January 8th for millions of our customers affected by the IRS error.  We expect most of these payments to be available that day, but banks could take a few business days to process. Payment will be deposited into the same bank account that customers received their 2019 tax refund.

Customers receiving a stimulus payment will receive an email from TurboTax letting them know their stimulus payment is on the way.  We have been working tirelessly with the Treasury and IRS to get stimulus payments to our customers.  We know how important these funds are for so many Americans and we regret that an IRS error caused a delay.

Please note the following page for additional information:  Why Haven’t I Received My Second Stimulus Check?