No 3g after restoring jailbroken iphone 3gs to factory settings?

Ok
Heres the scenario

>bought an iphone 3gs
>it was jailbroken
>removed jailbreak and restored using itunes
>now the phone has no 3g data

Contacted 02 and everything is fine on there end… Even got a new sim to be sure… Reset network settings a million times.drove around 30 miles away from my house and picked up 3g again, but when i went home i lost it again, something about switching mobile mast signals I've seen on forums. Running 6.1.3, completely stumped. I've tried restoring on itunes and setting it up as a new phone with no avail… Thanks for reading, any help is greatly appreciated

If you phone was jailbroken earlier, check the firmware version (Settings > General > About). If it shows an old ipad version, that could be your problem.

I've used a few 3gs phones in the past and have noticed their GPS strength is not as good as the iphone 4 in general. So it may just be time to upgrade!