VODACOM CHARTZ DAMAGED MY PHONE

my contract phone was damaged and i took it back where i bought it (vodacom chartz) and they booked it to their private technicians instead of taking it to vodacom repairs. the phone came back unfixed and only to find out that their private technicians have damaged the mother board of my phone. i then took the phone to vodacom repairs and they send it back telling me that\an unauthorised technician has worked on my phone and they have damaged the mother board. i ask them what to do because my phone is still under warrenty and they ask me to go back to the store to speak to the manager to give me another phone. i did spoke to the manager and they grabbed me by clothes telling me that i musnt come back again. here is the engineers'report