I need assistance it is reaaly urgent

Good day

I am writing this review with hope to be assisted. I bought an iPhone 14 with the mtn contract from soshanguve crossing On the 19th of December i was assited by Martha. after 15 days of purchase i encountered problems the phone was overheating the battery could not last a day then i called martha from crossing to assit me she suggest that i bring the phone in store so that they can take it to repair i did bring the phone back on the 14th of january. She's not doing any follow up on the case as a customer i have to remind her to chcek how is the progress i waited for her to call or text she didn't. i called her Yersteday to check if the phone is being fixed only to find out there's an email she got which implies that there's no way they can fix the phone that has a screen protector and its not on warranty . Its been 16 days the phone is still hanging. I am honestly devastated and frustrated can you kindly assit me so that i can get a new iphone 14 in good conditions.or cancel the contract. My sister went in store asked for assitant manager Jerry for assistance they informed her that they going to get back to me and they never did In this case i feel they sold me a phone that has already been used i called their Head office spoke to selia she insisted that i go to the store according to my understanding we call head office if we can't get any assistance but it seems like no one is willing to help me coz they know what's going on with the phone and worse part i am paying

Kind regards

Nqobile