Help Galaxy Ace GT-S5830 mobile network not available

[rodlus]

Hi I am based in the Uk I am om the three network when i insert my sim it wont register with the network. I try to use it to call and it tells me the obile netork is not available can anyone help please

 

[ayush29k]

Have you tried using the sim on a different device and a different sim on this device?
Just make sure if the problem is with the sim or the phone.