I had an issue at one time with FreedomPop not allowing my normal dialer to function, I could receive calls and not place any. I stumbled upon it when I opened the FreedomPop app and it immediately asked me if I wanted integrate with my dialer, since I hadn't opened the app since the upgrade that added that feature to FreedomPop I didn't even know it was waiting for me to chose. Once I clicked no, my dialer worked normally. Do you have any VOIP apps (that's what FreedomPop is) that you recently downloaded/had an update? That may be the cause of the issue if they recently setup to integrate with the native dialer, you may need to turn it off.