Service sucks

On 1 April 2018 I returned an incorrect device back to Vodacom that was sent to me; the device I ordered was not the device I received. On my upgrade they had changed the upgrade date to 2020; I have been battling since April 1st for them to revert it back to 2018 so that I can go to Vodacom and upgrade my daughters device to one that she actually wants. How pathetic is that? I have been to Vodacom itself and they said they had to escalate it; I have phoned the Call Centre on numerous occasions to ask them to fix it. I am on the "old" system so nobody can help me so they need to call me back - THEY NEVER DO. I have never in my entire life encountered such unbelievable bad service. I don't know what to do anymore I have exhausted all my resources.