Mobicell

I bought a phone from pep home last year december it was R1200 and around march it just stopped working.and i took it back to pep home cause it was still on warranty.now i have a massage from mobicel telling me i must pay R985 for repair if i reject to pay that i must pay R250 for rejection..no one told me about any charges.is not my fault that phone is not working..im not going to pay a cent they must pay my money back or they must repair that phone.Why would i pay that amount of money for something i didnt break..Ths doenst make sense.Why would i pay 985 for 1200 phone why??