Have you accessed the Help section inside the Find My Friends app by tapping on your own listing at the bottom of the map page? Or is your problem that you're not showing up there, either? You have to scroll all the way down to the bottom of the resulting page to find Help and then tap that. Not sure if there's anything pertaining to your situation but there is a section on Location with many subs and a Troubleshooting section, among others.
Which iOS are you using, BTW? Nothing changed for me when I upgraded to iOS 8.1.1. Sorry that you're having trouble on 2 (!) devices.
Please post your solution when you find it, in order to help The Next Guy.