Mobicel R6 is a useless phone!!!!!

Im Not happy with the Mobicel R6 phone, I bought it on the 21st August 2018 it froze on the 28th August 2018 took it back then they gave me another one , Was using it from the 28th until it froze completely on the 2nd November 2018, took back to Pep stores @ Dube in Soweto.. I want nothing to do with that phone all i want is my money back. i ended calling the Pep Contact Center was told the matter would be escalated to the regional manager and thy would call me back but up until now no-one has called back. Went to Maponya mall today at pep was told they can do nothing up until the manger or contact center has called... I use my phone for work and business use i cant wait for them to resolve my matter as i want my money back to purchase a different phone... I am mad as hell cause i find myself wasting money at going to the stores and calling where as im not being helped everywhere i go!! i'm a very angry and unhappy customer!!! PLEASE HELP