I had almost the exact same experience with Roni Lynn Deutch. How they stay in business is impossible to determine.
They strung me along for a year, sending financials over and over, finally they claimed to "negotiate" a payment instead of offer in comprimise (which I know now VERY PRECIOUS FEW QUALIFY FOR) the payment was 100 dollars less than the garnishment I was paying. I was pissed, called the IRS myself and in 15 minutes had it down to $500 from $750. when I fell behind on that, I then hired a real tax professional for $350 (an enrolled agent) and he helped me get a payment plan set up we could all live with, and now I am free of the IRS.
All of these rubber stamp tax firms are the same, take as much of your money as they can, do nothing but generate paperwork for you and the IRS. Once you have paid them off, they will dispose of your file as quickly as they can by "negotiating" a payment plan, that you could easily do yourself. if you are in real trouble, hire an Enrolled Agent in your town. Meet face to face and discuss options. Put Roni Lynn Deutch, JK Harris and all other crooks out of business. Deal locally or with the IRS yourself!