I recently bought a phone from cincinnati Bell, a 9771C, and it's not the best phone in the world. I'm on the 50$ unlimited monthly smartphone plan (I think it's a prepaid plan, though, sorry I don't know, my mom did all of the papers and stuff). I want to know if I will get an upgrade in a few months, and if so, is there a limit on the upgrade? Also, are smartphones supposed to come with an SD card, because mine did not. While we're here, I might as well address another problem. I got my phone about a week or so ago, and for the past couple of days, every time I try to call someone, It says Network Busy. I've tried multiple times, tried removing my battery and SIM card. Also, when other people call me, my phone doesn't ring or give any indication that someone is calling. My mother said it goes straight to voicemail. I anticipated something like this happening, so I left my screen cover on, and saved the box and all the papers. Should I just take my phone to the store, since I know I have a 30 day warranty, or is it something in my settings or something like that?

I know this is really long, but any help would be greatly appreciated.