If only one port is non-functional, that port is likely damaged.  Unfortunately, it's not a separately replaceable part.  If it's on an I/O board (this model has one), that will need to be replaced.  If it's on the mainboard, you will need to replace that to fix the issue. Service manual: [URL]  
Purchased Laptop close to two years ago and after about 1 year the left top USB C stopped working with all devices I've tried to connect to it including charger.  Have tried all the other suggestions in other posts including updating BIOS and other enabling, disabling lightning adapter options.  Any help would be appreciated before I order a replacement port.  Thanks.
USB-C not working XPS 9500