Firstly, because your phone is now jailbroken the software may now be faulty and you may have recurring problems with it.
But you should restore your iPhone as a new iPhone, it will wipe EVERYTHING, from the phone but it will also mean your working from a "clean" phone as it where, it will put it back to how it was from the day you took it out of the box.
Follow the details below to restore your iPhone as a new iPhone and then connect it back up to itunes with the sim inserted to activate it, also if you receive any messages on itunes about carrier settings, choose to update as these are what you need to have your network function. Although as I mentioned earlier, I cant guarantee you that your phone will be working and sorted as it is now jailbroken and doing this permantly alters the phones software.
Hope this helps (please leave feedback)
1 - Load up lateset itunes on your computer
2 - Power down your phone completely - swipe to power off
3 - Hold down the home button (circle button on front of phone) for around 6secs and still holding down connect to the computer
4 - When you receive a message on itunes saying that an iphone has been detected in recovery mode and needs to be restored. Continue with this
5 - On the summary page select the restore option
- When prompted to back up your settings before
restoring, select the Back Up option. If
you have just backed up the device, it is not necessary to create
another. **dont worry if your not asked to do this, you are restoring your phone as new so a back up isnt needed**
the Restore option when iTunes prompts you.
- Once the restore process has completed, the device restarts and displays the Apple logo while starting up:
After a restore, the iPhone displays the "Connect
to iTunes" screen. Keep your device connected until the "Connect to
iTunes" screen goes away or you see "iPhone is activated." If iTunes
does not have an Internet connection, you cannot complete this step.
final step is to restore your device as a new iphone