to replace a working motherboard

My s5 fell and the touchpad cracked .i did a back up of my stuff using the kies3 software minutes before my phone was picked up by adh couriers. That means that my phone was still in working order.about a week later samsung sent me an email stating that my claim has been processed to replace my screen.then a week later i recieve another email stating i have to pay R2500 to replace the motherboard.doesnt make any sense because my phone was still operational.my phone is not even a year old and Rauwina says that there is no warranty on my phone.i refuse to fall for this ****.adh is ripping people off thier money.Samsung needs to find another service department.