Lack of customer service

I bought a new Huawei P30 lite from MTN Geenstone in November, in January I started experiencing problem with the phone. The phone switched off by its self and did not want to switch on again no matter what I did. The phone also dropped signal alot and the battery would get very hot when charging. I booked the phone in at the MTN Eastrand mall for a warranty asessment. After a week I called to find out what is the problem with the phone and the repair center told me the phone is not yet with them. So I called the Eastrand mall branch to find out if the phone had gone.they told me the phone has been collected. So I gave it another week and called the repair center again and the still said the phone has not reached then, so u called MTN Eastrand mall agin and the then said there was a problem with DSV the courier company. 4 wekk later I called the repair center again only to be told the phone can not be traced and they dont know where it is. Since then i have been calling the Eastrand mall branch but there is no answer. At this point i am so angry and frustrated as that phone is used for my Business. PLEASE COULD YOU HELP