keyboard and touchpad is not work.

my mac is 2015 early release, In July of this year ,The keyboard and touchpad of my mac is not work, then i reset the smc, but it didn't work. and then i reinstall the os, but it just work a monment, so i send it to Genius Bar, they change the keyboard and touchpad, it can be used, but they didn't tell me why it happens. and now, the keyboard and touchpad it could'n be used again, when i want so send my mac to Genius Bar that i never get a date. so what should i do ?

who can tell me what's wrong with my mac.

thanks a lot.