Not recieving Calls or Texts!

This is getting Extremly Frustrating! I've had my iphone for a little over a month. When i purchased it, i was told coverage would be bad for a few months, and i understand this, but I'm just starting to wonder if the problems im experincing are not nesesarily based soley on the coverage of my phone.

It seems as though text messages i recieve wait in a queue until I send a message myself, and i then recieve all of the texts that have been piling up. I have sent somewhere near 300 messages to myself because of this problem.

I've also noticed at times when my signal strength displays full bars (at work right now) I don't recieve calls. I call myself using my work phone, and it rings twice, and goes to voicemail. If i turn airplane mode on and off, i can recieve calls for a few minutes and then it goes back to it's regular ways.

This doesn't happen all the time, which leads me to believe it is a signal problem as I was originally told, but you can never be too sure, right?

Aditional information, It's a tethered Jailbroken iphone 3gs, running on 3.1.2 jailbroken by blackra1n for windows.

 

Yea. I figured as much, just wanted to verify that it wasn't a phone problem. (Warranty is void becuase of a bs faulty water sensor in my earphone jack). I was told the network wouldn't be up and working properly until the end of january, so it IS starting to get a bit frustrating since that was over a week ago. Oh well, now that I know it's not only a problem with my phone, im not too concerned.