Iphone 3GS won't make phone calls?

I recently received an iphone as a present from my cousin (second hand) but I couldn't use my sim to use it. After some research I found that the problem could be fixed by unlocking myself, through jailbreaking. Unfortunately it was updated to the latest firmware (6.1.3) so I only managed to semi tether jailbreak it. I used redsn0w to do this and ultrasn0w to unlock. The phone successfully recognises I have an EE sim in and it gives me a signal however, when I try to make a phone call it beeps 3 times and says call ended or if I try to make a phone call as soon as I turn the phone on it says call failed. I have changed the caller ID to on but this doesn't seem to fix the problem for me at all and I have tried another (working) t-mobile sim which had the same problem. The iphone was originally on a vodaphone contract, if that information is important. Any help would be appreciated.

I have had this problem before and i rung vodafone up and i was kicking off Coz i just got a bb an wanted to go on bbm lol an all they said was its EE thats having the problems not u… I got told to take battery out but ov you can't do that so all i can say is take sim out switch it off… An leave it for 5 mins… Then go bk put sim in first an switch on…
good luck let me know how you get on. X

the only other thing it can b if its not your network is you have messed up unlocking it… And you will need to reboot it again so its bk to vodafone then just take it to a unlocking shop an pay £5… An then at least u wil know its done properly and that its goin to work… X