The C-Force have a driveshaft brake in the back and there isn't an adjustment. The entire brake system is 3 calipers/rotors. I haven't had an issue with squeaking, however my brake performance is awful.
On the newer cforce they removed one of the brake handles so you only have a right brake handle and a right foot pedal. I believe the handle and pedal activate all 3 calipers (2 front, 1 rear).
I would try giving CFMoto a call and see if they dealer should fix it, maybe your dealer is being lazy. My dealer has made two warranty repairs to my brakes (stuck calipers) maybe that is what's wrong with yours as well.