Please make sure you have put the instalment payments in the
correct place: https://turbotax.community.intuit.ca/replies/3226877
Also, in some instances, it is possible to pay too much in instalments,
and have them refunded by the CRA. The instalments are usually based on your
income from previous years, so if your income changes, then you may no longer
owe that much.
If you are still having issues, please contact our phone support
for further assistance. (*not available to TurboTax Free users*):
https://turbotax.community.intuit.ca/replies/3152013
