Stumped by this problem! With the phone. I have a handful of numbers (that I know of) that I can receive a call and text back and forth, but cannot call them. When it tries to dial it quits and the call log shows the call as cancelled. When I swap it in another phone, I do not have any problems with this SIM. I've reset network settings, deleted contacts, but am stumped. Any ideas before I send the phone back to Amazon? Thx!!!