I'm really sorry that you're having some trouble with using the touch screen on your phone. I want to get this all sorted for you. Are you able to hard reboot the phone by following these instructions:
Press and hold the Power button and the Volume Up button at the same time for approximately 15 seconds.
The device will vibrate 3 times, release the power and volume up buttons
Thanks for taking the time to let us know about this, as you're still experiencing the issue I'd recommend contacting our team so we can arrange for a handset repair. Either by phone, or by your 'My Account' section online.
You can get through on 0345 6000 789 from any phone line or 789 from your Virgin handset. You can also sign into your My Account by clicking [here] and take a look at the Phone Fix options.