Q: Screen has went blank?

I was listening to Apple Music and my phone looked like it turned off? Although when I pressed the home button in, Siri started to speak. So I know it is on, just cant do anything with it? Also cant do a "soft reset" as I am connected to my work wifi and it needs a password to connect.

Only had the iPhone 6 since August and it has already been sent for repair - been told there are many hardware issues that a complete wipe of my phone and icloud would resolve, which I agreed to and hasn't been the case. This repair is strangely not listed in my online "profile" and obviously cannot see the IMEI number in settings.

Seriously losing my faith in Apple now.