Keyboard and mouse not working - MacBook Pro 13" Early-2015

My 13" MacBook Pro Early-2015's keyboard and mouse has stopped working. I have tried to reset SMC, PRAM and NVRAM but these won't work due to the broken keyboard. Though the backlit key lights work (as this was set at full brightness when the keyboard did work), the caps lock button's green led does not light up when pressed. The only button which does work is the power on button. Using an external keyboard and mouse works but this is impractical as I have to carry it around with me all day. I have not dropped, bumped or damaged the laptop in anyway or changed any code/deleted any apple files. The NVRAM, PRAM and SMC won't reset with the external keyboard as this only works with the built in apple keyboard.

Any advice on how to fix it would be very appreciated!