My parents have accountants and ngl they are legit morons, I invest frequently so they just took my T5008 from my broker and just put in the numbers without even looking. My T5008 didnt say my cost basis for some reason so all my sells are capital gains saying I bought the shares at 0$. This made my Captial Gains line around like 20x more then what I actually gained, I even took a closer look - the returns are all in USD and my accountants didnt even care to do any conversations. I ended up fixing my return myself and refiling but I'm just wondering, if I never fixed this would I just be paying 20x more in taxes?? Like would the CRA tell me I fucked up and fix it for me? Refund the extra I paid, or would I just be screwed.