Bad experience twice in a row while trying to upgrade. I am leaving this network

I have a contract with vodacom, the last time I upgraded i battled to get an upgrade, right now I still battle to upgrade. I called in many time, since i am a less valued customer to Vodacom i decided to cancel my contract and keep my number for prepaid, i keep receiving the same bad experience. I am planning to port to another network after my cancellation which currently is a nightmare. I called so many times and consultants keep saying they have logged a request as to why can't I upgrade, since i am no longer interested in upgrading rather decided to keep my numbers for prepaid, i struggle to get assistance but consultants keep saying i will get a call after 7 days but its been months since I expected calls.