iPhone 3GS old SIM new handset

[Deb0rahB]

i've recently had to replace my damaged 3GS handset - put my old SIM in the new 3Gs handset and have been able to sync all the apps but can't seem to make phone calls or send/receive SMS messages.  On Pay and Go tariff. Any ideas on what I need to do? 

[Deb0rahB]

Just seen similar probs reported on iPhone 4 following latest software update - wondering if this is the same thing?

[jonsie · Accepted solution]

Go into your settings and try 'reset network settings'.

settings/general/mobile data/mbile data network/reset settings/reset

or try a hard reset by holding the home and sleep buttons till the apple logo appears

[Anonymous]

Try a restore via itunes or turn off & on in airplane mode