IF you do not have a second account...or for any account you do have.
1) Log into your Online Turbotax Software account
2) Go down to the lower left corner of the screen and click on "Intuit Account"
3) when yoru Intuit account shows up, click on "Data Privacy".
4) Scroll down the main window to find the "notifications" area for opting out of both Direct Mail, and possibly email communications (with some exceptions)
Might take a week or two to become effective.