Help PLz The service on my Iphone isn't working

[BetheBoss280@Gmail.com]

The service on my Jail broken Iphone isn't working

I jail broke and it all went smootly

but after like an hour the service stopped workin and it is either No bars, No service, Or SIM Card Invalid but the SIm message doesn't happin afton but I know THere is service becuase my sis's phone has service

PLz help I would rather not reboot through Itunes but if that is the only opinion I would like to know

 

[(DL)lovers]

Argh, I'm having the same problem, I have AT&T carrier.