iPad Pro home and lock button not working - help!

I have a 12.9" iPad Pro which I use daily for work and in the last few minutes my home and lock button have stopped working! The screen is working fine and is responsive per usual.

The only way I could get onto my iPad was plugging in the charger, and getting access to it by putting in my passcode. I am now on an app and can't get off.

Can anyone help?