Poor Unprofessional Service

What are we doing today? I'm not sure how to answer this...is it a trick question, but I'm beyond livid! The service I received from the manager at Mtn Soneike Mall Kuilsriver Cape Town left a bitter taste in my mouth. I took out a business contract with Mtn and got me the OPPO A74 5G...I had a problem from the start and informed them, when I speak on whatsapp the person on the other side of the line was not able to hear me and there is a strange sound on the phone...they booked the phone in and did a software upgrade! The phone came back, still being faulty. I spoke to the Manager Miemie at Mtn Soneike Mall and explained to her that I don't even have the phone for 6months, it's a business contract, and I chose MTN thinking they are reputable company, but to my dismay. Miemie said I need to bring in the phone for a warranty assessment, which I handed in on 23rd November 2022 in a good condition. A few weeks passed, I went in on the 12December 2022 only to find out the phone arrived on 09December 2022 and Miemie didn't have the time to contact me! I asked her what the outcome was as I have not received any feedback from MTN...I was then informed by Miemie the warranty assessment was declined due to a chip on the phone, I said to Miemie I am not going to take a phone that is going for repairs as I handed them a phone that had no chip. I have pics of the phone when I handed it in and clearly shows no damage! Her response to me was she doesn't know where the damage of the phone came about , I was also informed that they missing the ipods, which I went to fetch and brought it into the branch . Miemie was not available and Igshaan came to assist me when I explained to him the nature of my complaint and mentioned that I don't want a repaired phone he felt he had the right to shout at me "do you then want her (Miemie)to pay for your phone" I stood there in total disbelief as MTN pride themselves as being an International Brand, hence the reason I took out a business contract with you! I am utterly disgusted and totally disappointed in the service I received from Miemie and Igshaan at Mtn Soneike Mall. I am a business owner myself, and I take pride in the work I do...It saddens me to see that the level of your service has dropped and it's on a I do not care basis...they bind to a contract take it or leave it... Is there anyone that can assist me with my complaint?