Sony Xperia M2 Aqua (4G) Screen going black

[JLB0502]

Ive recently got the Sony Xperia M2 Aqua (4G) and have found that every time i make an outgoing call the screen goes black and i cant hang up or do anything. I have to wait for the person im ringing to hang up and sometimes the screen will come back but most often i have to hold the on/off button and volume up together for 10 seconds. Can anyone give me some advice please before i make a trip to the Vodaphone shop....  I only got the phone mid December 14, it has no protective screen on it and hasnt been dropped ect.

[DaveCD]

@JLB0502 

Please ensure you have the latest software for your phone.

If this is the case, back up your information and perform a factory reset.

If the issue still remains, find out what you need to do in order to get this sorted take a look at our Vodafone Repairs Thread. This can be found here.

DaveCD