If you are that far behind, you should seek help from a local tax professional.  Software is not available for years earlier than 2015 for TurboTax.  It is too late to seek a tax refund for any year earlier than 2015--and you only have until April 15, 2019 to get that refund (if you have one coming to you).  But if you owe tax due the IRS certainly wants you to pay.

You paid them?  How?  Did you know the amount for each year?  Did you send in separate payments for each year so they got applied to the right year?

Taxes were taken out of my pay but I haven't filed a return for the last 6 years.

<a rel="nofollow" target="_blank" href="https://www.irs.gov/uac/view-your-tax-account">https://www.irs.gov/uac/view-your-tax-account</a>