If you are using TurboTax Online, you should get asked about the Canada Workers Benefit during the review. You will be able to opt out of the credit there.

Hello, thanks for your reply. I have selected to opt out however this doesn’t work. The credit is always applied.

If you are still not able to resolve this issue, please contact our phone support team for more assistance. 

During tax season (from CRA NETFILE opening (mid-February) to the regular filing deadline (April 30), we're available 7 days a week during these hours:

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During the rest of the year (May 1 to mid-February), we're available Monday through Friday, 9 AM to 6 PM ET for English and French support.