I have a Galaxy S2 on Ting. To force the ICS update 3 weeks ago, and then today force the FH13 update, I performed the following steps:
1) Make sure phone is fully charged or is plugged into power (it's also is good to be on wi-fi)
2) Settings > Applications > All (tab at top)
3) scroll down and select Google Service Framework, Tap on Clear Data
4) go to system update and update PRL, then update Profile, then update android (aka Samsung Software).
5) if step 4 doesn't result in an update being applied, repeat steps 1 through 4. For some reason I sometimes have to do it twice before it works. It might be whatever step 3 is clearing gets "uncleared" if you're too slow -- not sure.
-Tom
By the way -- Ting is a great service -- you pay full price for the phone up front, but you make that back with the very low monthly costs (as long as you stay on wi-fi at home, your monthly charges are very low). Here is my return on investment spreadsheet for 4 phones -->
https://docs.google.com/spreadsheet/ccc?key=0Ag9JX5TNCrcBdGZ1RnYxWnlHQ0MydFEzaDF4NFlnTlE