If you owe more than you can pay right now, there are three options, short of bankruptcy, available to you. If you can't pay anything on a monthly basis, then the account needs to be declared "currently not collectible".
If you cannot pay all of it now, but you can pay some each month, then you are a candidate for an installment agreement. If the amount you can pay each month is not enough to pay off the amount owed over the next five years, then you are a possible candidate for an Offer In Compromise.