Mondo is a ****

I received a call from someone saying they are from MTN saying I am due for an upgrade so I accepted. 3 weeks later I get a statement from MTN where I am due to pay 4 times the amount. I called MTN to query - MTN explained that as part of the charges there is cancellation charge - I was not due for an upgrade - They then said they will transfer me to Mondo - Mondo says they will reverse the Upgrade - They did reverse the Upgrade now there is extra charges for doing that - I am due to pay more again this month for their mistakes. Taking a call from Mondo was the biggest mistake ever - I would not recommend to do any business with them - After numerous calls there is no refunds for all their mistakes on my line.