you need to claim all income, as you already figured out in this thread, it is totally your responsibility, if someone pays you cash to do work you must report italexgomes said:Hey is there a way, I can calculate income tax PROPERLY and accurately, So I went through everything and figured out from July 17 - Dec 30 2015 I made 17,500 that cra doesn't know about. If I could get a proper official income tax calculator then I could figure out how much total tax I'v not paid.
get studiotax (studiotax.com) and run through their free software, it is pretty easy to use
if you can't figure that out you should go to an accountant who shouldn't charge you much at all for such a simple case, but as someone already said you need to re-file and correct your previous return(s) that were missing income on them