MTN Retention Centre is bad

I opted for an upgrade on one of my numbers. A sim only deal. First I got a sms to say the upgrade was declined and then I got a sms to say it was approved. I received the bill on Friday the 20th of August and the amount was higher than was told to me over the phone. Yesterday I have been phoning MTN, wanting to cancel the upgrade. Spending over 3 hours on the phone explaining the problem and then getting told to phone another number and customer service agent putting you through to the retention department where you put the phone down after 30 minutes without the call being answered. Not he first time this happened to me. Every time you want to cancel a contract, this happens. Very poor service from MTN. # Win