From what I have heard, most if not all, of the IRS help companies are just rip offs. The last rehab house I bought was from a lady who claimed that she had paid a company $1000 that guaranteed she would not get foreclosed on. (Obviously that didn't work). The companies that will get rid of your debt apparently do work - but in order for it to work you have to destroy your credit. They have you stop paying all of your bills and then the credit card compaines figure they will never get anything from you so settle for pennies on the dollar. The settled (bad) debt follows you for YEARS. Don't even think about getting a credit card or buying a house for many years.
Instread of playing games with those who call you just tell them that you have no debt.