mtn repair issues

Good day. i have recently taken out a contract with mtn and have 2 other contracts with them. on this contract i had an iphone 5s that gave me trouble and i sent it for repairs, they then replaced the unit until that gave me issues aswell, i then decided to change to a j7 pro about 4 months ago and that worked fine until the charging port stopped working properly, the phone would vibrate continuously. the warranty assessment was approved by mtn. due to my troubles with previous devices ,i have decided now to change to a huawei p10 lite because i have been using a huawei device which i borrowed from work in this time that the j7 pro was booked in and it seems to work fine. the issue here is its taking extremely long and i need the phone. the service by the store is excellent and the person that helped me is kovan. he is excellent at what he does, the problem is the headoffice or repair centre that doesnt process stuff in time. its either you guys give me another device or cancel the contract . i wont pay R329 a month for something that doesnt work and isnt with me. i have had nothing but issues from i took out this contract. there was no physical damage and the phone was kept in a case. if warranty assessment was approved wht cant you guys just give me another device or cancel the whole thing? i would rather go and buy a device cash,it has been such a huge inconveinence removing information from one phone and moving to another. mtn you need to speed up your process because you will loose business not becuase of the staff at the store but because of your slow migration process. my reference number is i- ********** 2726 . please resolve this issue asap. i am not waiting another week! i have other contracts with you which intotal debit adds up to approximately R800 a month and im now double minded.