Owning back taxes to the IRS is dangerous. You should consult an attorney immediately as you do not want to be in trouble with a government agency, especially one that can make your financial situation even worse. Paying back those taxes, however, it oftentimes hard to do. There are many strategies and policies the taxpayer should be aware of in dealing with IRS debt.
When you do not have the full amount, and paying over time is nearly impossible for you, you are going to need to consider an offer in compromise. If you are eligible, you will be able to lower the amount owed and either pay it back in a lump sum or in a few installments. When you settle with IRS, you will not have to deal with this again. Unless you build your debt back up, this problem will be gone for good. You are agreeing to pay a smaller amount now and have this gone forever. Just remember that this smaller amount is not always going to be dramatically smaller. The IRS wants this to be easy on you so that you are more likely to give them at least some of the money owed, ensuring that it is not a total loss on their part.
Not everyone is going to be eligible. Tax debt relief is not something that is available to all people, something that you have to keep in mind when trying to find help. You may not qualify for this, possibly because of income or asset value, so look into everything beforehand. You need to make sure that everything fits with the eligibility requirements of an offer in compromise. Look into it and other ways to settle with IRS so that you are informed and choosing the best option for you
Experience, Knowledge, Sophistication, and Education of Taxpayer