Taxes

If you had cash income then YOU are the one who pays the tax on that income--not the person who claimed you as a dependent.  If you had even $400 of income that you received as an independent contractor then you are required to file a tax return and pay self-employment tax for Social Security and Medicare, and possible ordinary income tax, depending on how much you made.  If you did not work for an employer who gave you a W-2 with tax withheld, then the IRS considers you to be self-employed if you worked for cash.

We do not know any of your details so we cannot say if you could still be claimed as someone else's dependent--we do not know your age, whether you were a full-time student, etc. etc.  It is possible that you could still be claimed as someone else's dependent even if you had some income of your own.

https://ttlc.intuit.com/questions/2903027-how-do-i-report-income-from-self-employment

https://ttlc.intuit.com/community/self-employed/help/what-is-the-self-employment-tax/00/25922

https://ttlc.intuit.com/questions/2902389-why-am-i-paying-self-employment-tax

https://ttlc.intuit.com/questions/1901340-where-do-i-enter-schedule-c

https://ttlc.intuit.com/questions/3398950-what-self-employed-expenses-can-i-deduct

Do you  meet the criteria to be claimed as someone else's qualifying child or qualifying relative?  If so , on your own tax return you must say that you can be claimed as someone else's dependent.

WHO CAN I CLAIM AS A DEPENDENT?

You can claim a child, relative, friend, fiance (etc.) as a dependent on your 2019 taxes as long as they meet the following requirements:

Qualifying child

• They are related to you.

• They cannot be claimed as a dependent by someone else.

• They are a U.S. citizen, resident alien, national, or a Canadian or   Mexican resident.

• They are not filing a joint return with their spouse.

• They are under the age of 19 (or 24 for full-time students).

• No age limit for permanently and totally disabled children

  •      They live with you for more than half the year (exceptions apply).

Qualifying relative

• They don't have to be related to you (despite the name).

• They cannot be claimed as a dependent by someone else.

• They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.

• They are not filing a joint return with their spouse.

• They lived with you the entire year.

• They made less than $4200  (not counting Social Security)

• You provided more than half of their financial support. More info

When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them.

Related Information:

• Does a dependent have to live with me?

• What does "financially support another person" mean?

• Can I claim a newborn baby?

So my ex fiance, We were not married claimed me as a dependent in 2018 and 2019. We lived together. I am 27.

Since you were without a doubt over the age of 23 in both tax years, and you earned more than $4,200 in both tax years, you can not be claimed as a dependent on "any" tax return. Period.

You personally are required to file a tax return for those years if you had more than $12,000 in gross earned income in either tax year.

And each year i made about 12000 in cash.

Regardless of your income amount, if any taxes were withheld from your income and your income was less than $12,000, then you "should" file a tax return to get all that withheld tax money refunded to you.

Note that weather you file a return or not, your ex needs to amend her tax returns for both years to remove you as a dependent and she can expect to have to pay back a few bucks to the IRS when she does. If she doesn't do this on her own, then when the IRS auditors catch up with her (and rest assured they will) the fines and penalties that will be imposed for claiming a dependent she didn't qualify to claim, will be quite a bit higher.