When they call me on my iphone 2g OS3s all calls go straight to voice mail

Basically, if this is the case you take your device back to the shop. If you need a solution before then though, search in google for 'iPhone firware 2g 2.2.2'. This firmware should support calls. Download the IPSW. Simply put you r phone into DFU mode (you can google how to do this). Then connect your phone to your PC. Then open iTunes. Click on the tab "*****'s Iphone". You should see the 'Restore' button. Click this WHILST HOLDING DOWN "SHIFT" (on the keyboard). Then a file browser should appear. Select the previously downloaded IPSW, and iTunes should do the rest. Simples :)