Am I correctly filing with the IRS during my N-400 visa process?

I have worked as an independent contractor before. I have worked for several agencies (promo model) and I did not really track it down. but the certain thing is, I didn't make enough money to report to IRS. (Under $400) I tried to file a tax return even it was a little bit , but the agencies simply refused claiming they don't send a form if I don't make $600 from each agencies. so I couldn't get 1099 form. So I didn't file for tax return. I was married, so I filed joined tax but got a divorce for a domestic violence (with a police report) after 3 years of marriage. so I am waiting 5 years to file my N-400 like other green card holders(instead of 3years) but since I failed to file my taxes in past, I have to say No, to the question "Have I ever failed to file taxes (or pay taxes)" its because my parents basically support me ever since a divorce. Should I need a letter from them or something to prove it? Also, to write about my work experience and school for past 5 years, should I write the agencies I worked as an independent contractor? Do I need additional proof why I didn't make enough money or should I just not state it since it's not a regular job, agency said they didn't report anything (neither do I) because we don't fulfill the minimum requirement to file taxes? Or am I just good just stating I have worked but didn't make enough money so didn't file anything and the law immigration officer would understand? I don't want them to doubt me for tax fraud or nothing.