Contract Breach by Vodacom - still no phone- but i PAY every month!!!!!!

I dont know what to do anymore. I pay for a contract with a phone. the phone Vodacom supp**** is faulty. they want to replace it. i must pay in R1500. They agree its their fault. but i must pay. Am i missing something. i have been paying for 5 months already and did not have the use of the phone. if someone from Vodacom contacts me. please let it be someone outside the call centre. please please please i want to speak with someone who are authorized to make a desicion.