XPS 13 touchpad only works on part of the pad

My touchpad works but has developed an unresponsive area in the bottom left corner. Sometimes it works but mostly not. The pad clicks but the cursor is unresponsive. 

I've applied pressure in case there's any dirt causing the problem, I've run troubleshooters, and I've checked the drivers. The problem persists.

The pad is also slightly uneven with the left side slightly low and the bottom right side elevated a little. It may have always been like that but I've only noticed since the problem arose.  I've had the laptop for about 18 months.

I'm hoping this is a software and not a hardware issue and any suggestions are welcome. Thank you.