Cellular issue - Others cannot hear me and I cannot hear them

I have an iphone 5 that is having issues with I make phone calls. I cannot hear anything when making a call and other cannot hear me. Both the speaker and ear piece are working fine because both functions work when using skype, textfree and textplus to make a phone call. It shows connection to the network like normal but for some reason when placing the call nothing can be heard.

I have tried to restore the iphone multiple times with no luck. It could have been on IOS 8.0.2 but it is currently updated to 8.1 so I am not sure what the issue is. To my knowledge this phone has never been opened or had any repair made to it. Could there be anything inside of the device that got loose or could be replaced to fix this.

Thank you in advance for your reply.