Gevey sim is invented by the chinese and bcoz it alwz requires to keep the sim between interposer and the iPhone 4 baseband hardware, i agree there could be some network outage..that is my thinking...or possibly its just the problem with ur service provider and could be sorted just by changing the network???
try changing the network and i see what happens???????if its the network issue it will be rectified and if its the gevey issue , may be u will have to get in touch with the technical support of their..