MTN Retentions Department

I went to a MTN store yesterday to cancel my contract. They said I should call 135 to cancel. I tried so many times, but I get cut off before someone answers the call. A lady then helped to log the cancellation, but said someone from the Customer Call Centre will phone me to confirm the cancellation, or I can phone 135. At this moment I've been on the line for an hour and 22 minutes, still holding. They're putting me through from one department to another and no one can help. My contract is supposed to be cancelled today, but I'm having no luck so far.