I have this problem, my old age pension got doubled. How can I refile, I have received a Notice of Adjustment.
@Robyn115 This TurboTax FAQ tells you how you can change your filed return:
https://turbotax.community.intuit.ca/turbotax-support/en-ca/help-article/accounting-bookkeeping/filed-tax-return-still-make-changes/L992Trv7f_CA_en_CA?uid=luvvx6t6