I am using an unlocked (formerly AT&T) phone. It is an HTC First, android version 4.1.2. I am currently using it in southern Ontario (Toronto-Peterborough area). I have had it since May and it was working without any issue. Just recently I have been unable to send or receive calls with consistency. It doesn't seem to matter how many bars I have, it just suddenly will stop working. It will say "dialing" and then just hang up. People calling me will sometimes go directly to voicemail or they will not get any dial at all. I checked my account, I have minutes on it, more than enough to make or receive a call. I am able to send and receive texts no problem. I am currently using the Koodo access point: sp.koodo.com Any advice here? It is frustrating.