Did you already get charged? You can sign into your Turbo Tax Advantage account and under Your Product, select to Remove Product. Once you remove the recurring product order, the Turbo Tax Advantage subscription will be cancelled as well.
If you missed the date to cancel, see the Tip in this
https://ttlc.intuit.com/questions/1901052-cancelling-or-refunding-your-turbotax-advantage-enrollment...
