MTN bad service

I got a call yesterday that I am due for an upgrade and they called me again this morning so I thought let me upgrade as I have nothing to lose. then I went to the MTN store in Eastrand mall around 9H00 and spent 2 hours at the store with their system down with the poor guy trying. He then called their head office in Centurion and they asked for a document from 2015 as I suffered *****. (to MTN) why did you guys calla me top go upgrade and the ask me for **** from 2018 and how did I open a new contract in 2018 without that same ****en document. I wasted 2 hours in your store waiting for your system and now I have to explain at work why it took me so long to when I asked for just half an hour. why did you guys call me to go upgrade in the first place. ***