What service are you referring to?  The software? You do not pay to use Netfile you pay to use the software to do your taxes.

I got as far as where you submit, then I’m asked for payment.  I was under the impression that this was free

Did you use the free version? Did you upgrade from the free?

I wanted the free version.  Can you help me send it in?

If you have upgraded to the paying version you will either have to pay or start a new return in the FREE (do not upgrade when asked)

Here is the link to the FREE version : https://turbotax.intuit.ca/personal-tax-software/free-online.jsp

Please review the link below to explain the process of filing late:

Do I have to pay interest for filing my tax return late or paying my balance late?https://turbotax.community.intuit.ca/replies/2648001