Extremely disappointing service from Truworths LTT

I am writing as a very concerned and frustrated client. I bought an MTN cellphone from Truworths store in Louis Trichardt on the 07th September 2020 on account, late on the 10th September 2020 the phone stopped working and couldn't power up. I took the phone back to the store on the 11th September hoping that the store will exchange it for since I only had the phone for only 4 days and still within the 7 days replacement period. Despite that, the lady manager told me that she has to book the phone in for assessment and will get back to me within 24 hours which has not been done. On the 21st September I called MTN regarding this and they said the store should have given me another phone. I went back to the store on the 22nd September and found a male manager who seemed not to know how he can help me. I have not been having a phone for 2 weeks now and they now surely expect me to pay for a phone that I don't have. I am extremely disappointed with the service.