If you are referring to the Advantage account where the software is sent to you automatically each November for the current tax year then see this TurboTax support FAQ for canceling the Advantage subscription and receiving a refund of any purchased software - https://ttlc.intuit.com/community/downgrading/help/how-do-i-cancel-my-turbotax-advantage-subscription/01/25548
I want to cancel my account which includes my return for 2019. Please credit my account that pays for TurboTax
TurboTax accounts cannot be canceled, but you can clear out the data you entered for a tax return if you have not registered, paid or filed. No one else can access your account so you can also just abandon it.
CLEAR AND START OVER
https://ttlc.intuit.com/questions/2586254-how-do-i-clear-and-start-over
No one in the user forum can resolve a billing issue.
To call TurboTax customer support
https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number
They are available from 5 a.m. to 5 p.m. Pacific time Monday-Friday