I am having Sony Xperia m4 Dual sim phone.From one month onwards my phone is not connected to any outgoing calls and for incoming calls touch is not responding to lift the call.if it is respond to lift the call,unable to hear the voice, for browsing suddenly signal goes to nill . I complaint to network provider, they given suggestion is ,try the same sim in other handset or other mobile.I tried in other mobile ,there is no network issue.hence please do the needful.