I filed a new return but am still getting the same answer that the CRA are keeping my 1st submission how can I get them to accept this one?
You can only file one tax return per tax year. If you submitted your return to CRA already, any changes must be made by an adjustment. If you're a CRA My Account holder, you can make these changes online in your CRA My Account using the "Change a return" option. This is the easiest way to make an adjustment.
If you're not a CRA My Account holder, you can submit an adjustment by completing a T1ADJ form and submitting it by mail.
It's faster to just set up a CRA My Account. The registration process is much quicker than the time it takes for CRA to process a paper adjustment.