Replacement phone taking 9 months now still paying

I upgraded online 2019 - End Nov and every time i take a photo or even whatsapp it jumps back to my home screen ! If i scroll to fast it jumps back to my home screen! After that it started to say storage full which was impossible! So i let them know i want to send it back in Jan 2020 i was able go replace the device and not just send it in ! It went in for warranty assessment they said as soon as they have stock they release my new phone ( this itself was such a big issue but Nevia sorted it quickly a week or so later then she told me in advance i will have to wait due to No stock of the iphone and Lockdown so when level 4 started i asked whether they have stock because my husband upgraded from Vodacom! Nevia then said she thought i received the phone already ! A few weeks later Nevia said that the new Phone cannot be released due to the RMA code ! I now need to cancel my contract and upgrade again but this was already after 6 months of payment ! I refused and said they need to figure this out very quickly ! So melissa called from MTN and said she will get back to me the next day! So a few weeks passed and no feedback not even a reply van Nevia or melissa ! So i contacted MTN many times and everytime someone else say they will sort it out very soon ! A few weeks passed and i contacted MTN where i explain the situation and they send new replacement forms which we completed ! And returned ! Then again no reply on her cell or email ! I called again ending up talking to melissa ! She said that she is offline at that moment and will get back to me the next day ! So i took het personal number ( or she said it was her personal number ) since then another week or so passed and still nothing 9 months later !!! And still paying ! This service is up to **** !