NACA services are free............this is from the Home Save eligibility page.
Given the current mortgage crisis NACA has suspended any Membership Fee for Home Save participants. In addition, NACA will pay for accessing your credit reports. All of NACA’s services are Free.
Citigroup is a supporter of NACA
https://www.naca.com/about_naca/citigroup.jsp
What that means is that Feb. 24th they will have an answer one way or the other on the file. If the modification is denied or is only for a five year period...............at that time then you may want to try NACA.