BAD SERVICE!

I changed my packages on two cell phone contract in August 2020.I was informed that I will still pay the normal fee on the contract until end of August 2020,thereafter I will pay the reduced fee as from end of September 2020.To my surprise when I asked for the invoice on my two contracts it is even higher than what my old fee was.I lodged a complaint at 8:00 this morning and I was told somebody will call me by 10:00.It is now 17:26,still no call or sign of MTN.How do you like that for service after I have been a client of them for 20 years plus???/