Poor Services and unprofessional

Good day MTN Mondo rewards.

I have been trying to get hold of MTN rewards center since they did a migration on my contract of which I'm no longer comfortable with it and I would like to cancel it since I was advise that I do have a 10 day period to view or cancel this reward for MTN Sky Bronze. I wanted something similar with unlimited calls and more GB which I can afford and since then my Issue is that we have been waiting for the invoice and till today there no invoice but huge amount i must pay . Its definitely a ******* on my case. Its really poor service provided.