MTN customer care sucks!

I have been calling customer care on 135 to cancel my contract as it ends next month but the consultants from MTN keep dropping my calls. I'd wait for a whole 15 to 20 minutes only to have your consultants drop my calls. MTN outlets says they can't help me with the cancellation of my contract and tells me to call 135. I've been calling for the past week , early as 7 am ,8 am and afternoons but still no change. I'm highly disappointed in your services MTN. It's funny how when a client is in arrears you are able to quickly get through demanding payments yet you can't prioritise your client needs!