Very Good qustion!
1. 1st you should contact with your inactive CSA and motivate him/her for SFI business via email or team message.
2. Encourage him/her and tell details about SFI and also tell about your success in SFI.
3. Give him some Tcredits or gift certificate for support/motivation.
4. If they provide contact numbers and if it is possible you should contact him/her via telephonically.