system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can someone call a phone number they heard on the radio and get "80% of their IRS debt completely gone!"

Are you in debt with the IRS? Do you have $20,000 or more in back taxes? Call this number for IRS relief!
gpt
Some of these businesses are scams, but some are legal and just charge for a service that anyone has access to.

For instance, people in a lot of debt to the IRS can make an "offer in compromise." They agree to pay a good chunk of their debt within a set time, based on their income and assets, and the IRS does not collect the rest of the debt. This is something the IRS does because a partially collected tax debt is better than nothing. 

Companies like these might do something like charge you up front to submit the application for an offer in compromise, even though that's something you can do yourself, if you knew about it.