No Cellular Signal. Cant Make Phone Calls or send texts.

[ShaheryarKhan]

Hi, I be really grateful if you could help me out, My Phones been working perfectly well ( xperia Ultra Z ) but its been two days since the signals keep dropping off because of which I cant make phone calls or send text messages. the Signals bar on the top shows Full network signals but when I make a call they dissappear and the call is cancelled and it gives off a beep. I reset the phone twice and that didnt help. 

Please help out, don't really know what else to do. 

[Thommo]

This is normally because the phone has been blocked from working on said network or without been horrible, you haven't paid your bill or have no credit

[ShaheryarKhan]

I have a prepaid connection. Its the phone not the network, if it had something to do with the network the same simcard wouldnt work on a different cell.

[SophiaW]

Hi ShaheryarKhan

Does the sim card icon at the top of your screen have a red X over it?