While it can be frustrating, it’s common for the Canada Revenue Agency (CRA) to make a tax return assessment that is different from yours. Please see this TurboTax FAQ for more information: Why is the tax refund or balance owing on my notice of assessment different from what TurboTax calculated?
If you have TurboTax Live Assist & Review, see this TurboTax FAQ to learn how to talk to a Tax Expert or book a review: In TurboTax Live Assist & Review, how do I talk to a tax expert?