Full Refund- Shocking Service

Hey It is really Upsetting that MTN do these thing to their clients. I sent my phone for repairs on the 26th June and now just over 2 months later my screen is coming loose and sometimes my screen doesn’t work. I paid over R2500 rand for this service. It is unacceptable and POOR Customer Service I want a complete Refund for this Service. So Again I must sit without a phone for 3 - 6 weeks. I want a complete Refund from the repair centre because now from their Stupid mistake a mess up i have to send my phone away again. Could you please provide me with an email address for you and the main person at the repair centre i want answers and i want it now